Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0-only
2 : : /*
3 : : * mm/mmap.c
4 : : *
5 : : * Written by obz.
6 : : *
7 : : * Address space accounting code <alan@lxorguk.ukuu.org.uk>
8 : : */
9 : :
10 : : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 : :
12 : : #include <linux/kernel.h>
13 : : #include <linux/slab.h>
14 : : #include <linux/backing-dev.h>
15 : : #include <linux/mm.h>
16 : : #include <linux/vmacache.h>
17 : : #include <linux/shm.h>
18 : : #include <linux/mman.h>
19 : : #include <linux/pagemap.h>
20 : : #include <linux/swap.h>
21 : : #include <linux/syscalls.h>
22 : : #include <linux/capability.h>
23 : : #include <linux/init.h>
24 : : #include <linux/file.h>
25 : : #include <linux/fs.h>
26 : : #include <linux/personality.h>
27 : : #include <linux/security.h>
28 : : #include <linux/hugetlb.h>
29 : : #include <linux/shmem_fs.h>
30 : : #include <linux/profile.h>
31 : : #include <linux/export.h>
32 : : #include <linux/mount.h>
33 : : #include <linux/mempolicy.h>
34 : : #include <linux/rmap.h>
35 : : #include <linux/mmu_notifier.h>
36 : : #include <linux/mmdebug.h>
37 : : #include <linux/perf_event.h>
38 : : #include <linux/audit.h>
39 : : #include <linux/khugepaged.h>
40 : : #include <linux/uprobes.h>
41 : : #include <linux/rbtree_augmented.h>
42 : : #include <linux/notifier.h>
43 : : #include <linux/memory.h>
44 : : #include <linux/printk.h>
45 : : #include <linux/userfaultfd_k.h>
46 : : #include <linux/moduleparam.h>
47 : : #include <linux/pkeys.h>
48 : : #include <linux/oom.h>
49 : : #include <linux/sched/mm.h>
50 : :
51 : : #include <linux/uaccess.h>
52 : : #include <asm/cacheflush.h>
53 : : #include <asm/tlb.h>
54 : : #include <asm/mmu_context.h>
55 : :
56 : : #include "internal.h"
57 : :
58 : : #ifndef arch_mmap_check
59 : : #define arch_mmap_check(addr, len, flags) (0)
60 : : #endif
61 : :
62 : : #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
63 : : const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN;
64 : : const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX;
65 : : int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS;
66 : : #endif
67 : : #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
68 : : const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN;
69 : : const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX;
70 : : int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS;
71 : : #endif
72 : :
73 : : static bool ignore_rlimit_data;
74 : : core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644);
75 : :
76 : : static void unmap_region(struct mm_struct *mm,
77 : : struct vm_area_struct *vma, struct vm_area_struct *prev,
78 : : unsigned long start, unsigned long end);
79 : :
80 : : /* description of effects of mapping type and prot in current implementation.
81 : : * this is due to the limited x86 page protection hardware. The expected
82 : : * behavior is in parens:
83 : : *
84 : : * map_type prot
85 : : * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
86 : : * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
87 : : * w: (no) no w: (no) no w: (yes) yes w: (no) no
88 : : * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
89 : : *
90 : : * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
91 : : * w: (no) no w: (no) no w: (copy) copy w: (no) no
92 : : * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
93 : : */
94 : : pgprot_t protection_map[16] __ro_after_init = {
95 : : __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
96 : : __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
97 : : };
98 : :
99 : : #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT
100 : : static inline pgprot_t arch_filter_pgprot(pgprot_t prot)
101 : : {
102 : : return prot;
103 : : }
104 : : #endif
105 : :
106 : 1405551 : pgprot_t vm_get_page_prot(unsigned long vm_flags)
107 : : {
108 : 1405551 : pgprot_t ret = __pgprot(pgprot_val(protection_map[vm_flags &
109 : : (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
110 : : pgprot_val(arch_vm_get_page_prot(vm_flags)));
111 : :
112 [ + - ]: 17997 : return arch_filter_pgprot(ret);
113 : : }
114 : : EXPORT_SYMBOL(vm_get_page_prot);
115 : :
116 : 746292 : static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
117 : : {
118 : 746292 : return pgprot_modify(oldprot, vm_get_page_prot(vm_flags));
119 : : }
120 : :
121 : : /* Update vma->vm_page_prot to reflect vma->vm_flags. */
122 : 746208 : void vma_set_page_prot(struct vm_area_struct *vma)
123 : : {
124 : 746208 : unsigned long vm_flags = vma->vm_flags;
125 : 746208 : pgprot_t vm_page_prot;
126 : :
127 [ + + ]: 746208 : vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags);
128 [ - + ]: 746208 : if (vma_wants_writenotify(vma, vm_page_prot)) {
129 : 0 : vm_flags &= ~VM_SHARED;
130 [ # # ]: 0 : vm_page_prot = vm_pgprot_modify(vm_page_prot, vm_flags);
131 : : }
132 : : /* remove_protection_ptes reads vma->vm_page_prot without mmap_sem */
133 : 746208 : WRITE_ONCE(vma->vm_page_prot, vm_page_prot);
134 : 746208 : }
135 : :
136 : : /*
137 : : * Requires inode->i_mapping->i_mmap_rwsem
138 : : */
139 : 1722903 : static void __remove_shared_vm_struct(struct vm_area_struct *vma,
140 : : struct file *file, struct address_space *mapping)
141 : : {
142 [ + + ]: 1722903 : if (vma->vm_flags & VM_DENYWRITE)
143 : 385980 : atomic_inc(&file_inode(file)->i_writecount);
144 [ + + ]: 1722903 : if (vma->vm_flags & VM_SHARED)
145 : 105 : mapping_unmap_writable(mapping);
146 : :
147 : 1722903 : flush_dcache_mmap_lock(mapping);
148 : 1722903 : vma_interval_tree_remove(vma, &mapping->i_mmap);
149 : 1722903 : flush_dcache_mmap_unlock(mapping);
150 : 1722903 : }
151 : :
152 : : /*
153 : : * Unlink a file-based vm structure from its interval tree, to hide
154 : : * vma from rmap and vmtruncate before freeing its page tables.
155 : : */
156 : 2041640 : void unlink_file_vma(struct vm_area_struct *vma)
157 : : {
158 : 2041640 : struct file *file = vma->vm_file;
159 : :
160 [ + + ]: 2041640 : if (file) {
161 : 1722903 : struct address_space *mapping = file->f_mapping;
162 : 1722903 : i_mmap_lock_write(mapping);
163 : 1722903 : __remove_shared_vm_struct(vma, file, mapping);
164 : 1722903 : i_mmap_unlock_write(mapping);
165 : : }
166 : 2041640 : }
167 : :
168 : : /*
169 : : * Close a vm structure and free it, returning the next.
170 : : */
171 : 2041640 : static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
172 : : {
173 : 2041640 : struct vm_area_struct *next = vma->vm_next;
174 : :
175 : 2041640 : might_sleep();
176 [ + + + + ]: 2041640 : if (vma->vm_ops && vma->vm_ops->close)
177 : 70014 : vma->vm_ops->close(vma);
178 [ + + ]: 2041640 : if (vma->vm_file)
179 : 1722903 : fput(vma->vm_file);
180 [ - + ]: 2041640 : mpol_put(vma_policy(vma));
181 : 2041640 : vm_area_free(vma);
182 : 2041640 : return next;
183 : : }
184 : :
185 : : static int do_brk_flags(unsigned long addr, unsigned long request, unsigned long flags,
186 : : struct list_head *uf);
187 : 109610 : SYSCALL_DEFINE1(brk, unsigned long, brk)
188 : : {
189 : 54805 : unsigned long retval;
190 : 54805 : unsigned long newbrk, oldbrk, origbrk;
191 : 54805 : struct mm_struct *mm = current->mm;
192 : 54805 : struct vm_area_struct *next;
193 : 54805 : unsigned long min_brk;
194 : 54805 : bool populate;
195 : 54805 : bool downgraded = false;
196 : 54805 : LIST_HEAD(uf);
197 : :
198 [ + - ]: 54805 : if (down_write_killable(&mm->mmap_sem))
199 : : return -EINTR;
200 : :
201 : 54805 : origbrk = mm->brk;
202 : :
203 : : #ifdef CONFIG_COMPAT_BRK
204 : : /*
205 : : * CONFIG_COMPAT_BRK can still be overridden by setting
206 : : * randomize_va_space to 2, which will still cause mm->start_brk
207 : : * to be arbitrarily shifted
208 : : */
209 : : if (current->brk_randomized)
210 : : min_brk = mm->start_brk;
211 : : else
212 : : min_brk = mm->end_data;
213 : : #else
214 : 54805 : min_brk = mm->start_brk;
215 : : #endif
216 [ + + ]: 54805 : if (brk < min_brk)
217 : 35952 : goto out;
218 : :
219 : : /*
220 : : * Check against rlimit here. If this check is done later after the test
221 : : * of oldbrk with newbrk then it can escape the test and let the data
222 : : * segment grow beyond its set limit the in case where the limit is
223 : : * not page aligned -Ram Gupta
224 : : */
225 [ - + ]: 18853 : if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk,
226 : : mm->end_data, mm->start_data))
227 : 0 : goto out;
228 : :
229 : 18853 : newbrk = PAGE_ALIGN(brk);
230 : 18853 : oldbrk = PAGE_ALIGN(mm->brk);
231 [ - + ]: 18853 : if (oldbrk == newbrk) {
232 : 0 : mm->brk = brk;
233 : 0 : goto success;
234 : : }
235 : :
236 : : /*
237 : : * Always allow shrinking brk.
238 : : * __do_munmap() may downgrade mmap_sem to read.
239 : : */
240 [ + + ]: 18853 : if (brk <= mm->brk) {
241 : 456 : int ret;
242 : :
243 : : /*
244 : : * mm->brk must to be protected by write mmap_sem so update it
245 : : * before downgrading mmap_sem. When __do_munmap() fails,
246 : : * mm->brk will be restored from origbrk.
247 : : */
248 : 456 : mm->brk = brk;
249 : 456 : ret = __do_munmap(mm, newbrk, oldbrk-newbrk, &uf, true);
250 [ - + ]: 456 : if (ret < 0) {
251 : 0 : mm->brk = origbrk;
252 : 0 : goto out;
253 [ + - ]: 456 : } else if (ret == 1) {
254 : 456 : downgraded = true;
255 : : }
256 : 456 : goto success;
257 : : }
258 : :
259 : : /* Check against existing mmap mappings. */
260 : 18397 : next = find_vma(mm, oldbrk);
261 [ + - - + : 18397 : if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
- + ]
262 : 0 : goto out;
263 : :
264 : : /* Ok, looks good - let it rip. */
265 [ - + ]: 18397 : if (do_brk_flags(oldbrk, newbrk-oldbrk, 0, &uf) < 0)
266 : 0 : goto out;
267 : 18397 : mm->brk = brk;
268 : :
269 : 18853 : success:
270 [ + + + - ]: 18853 : populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0;
271 [ + + ]: 18853 : if (downgraded)
272 : 456 : up_read(&mm->mmap_sem);
273 : : else
274 : 18397 : up_write(&mm->mmap_sem);
275 [ - + ]: 18853 : userfaultfd_unmap_complete(mm, &uf);
276 [ - + ]: 18853 : if (populate)
277 : 0 : mm_populate(oldbrk, newbrk - oldbrk);
278 : 18853 : return brk;
279 : :
280 : 35952 : out:
281 : 35952 : retval = origbrk;
282 : 35952 : up_write(&mm->mmap_sem);
283 : 35952 : return retval;
284 : : }
285 : :
286 : 9207378 : static inline unsigned long vma_compute_gap(struct vm_area_struct *vma)
287 : : {
288 : 9207378 : unsigned long gap, prev_end;
289 : :
290 : : /*
291 : : * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
292 : : * allow two stack_guard_gaps between them here, and when choosing
293 : : * an unmapped area; whereas when expanding we only require one.
294 : : * That's a little inconsistent, but keeps the code here simpler.
295 : : */
296 : 9207378 : gap = vm_start_gap(vma);
297 [ + + ]: 9207378 : if (vma->vm_prev) {
298 [ + + ]: 9064368 : prev_end = vm_end_gap(vma->vm_prev);
299 [ + + ]: 9064368 : if (gap > prev_end)
300 : 2330497 : gap -= prev_end;
301 : : else
302 : : gap = 0;
303 : : }
304 : 9207378 : return gap;
305 : : }
306 : :
307 : : #ifdef CONFIG_DEBUG_VM_RB
308 : : static unsigned long vma_compute_subtree_gap(struct vm_area_struct *vma)
309 : : {
310 : : unsigned long max = vma_compute_gap(vma), subtree_gap;
311 : : if (vma->vm_rb.rb_left) {
312 : : subtree_gap = rb_entry(vma->vm_rb.rb_left,
313 : : struct vm_area_struct, vm_rb)->rb_subtree_gap;
314 : : if (subtree_gap > max)
315 : : max = subtree_gap;
316 : : }
317 : : if (vma->vm_rb.rb_right) {
318 : : subtree_gap = rb_entry(vma->vm_rb.rb_right,
319 : : struct vm_area_struct, vm_rb)->rb_subtree_gap;
320 : : if (subtree_gap > max)
321 : : max = subtree_gap;
322 : : }
323 : : return max;
324 : : }
325 : :
326 : : static int browse_rb(struct mm_struct *mm)
327 : : {
328 : : struct rb_root *root = &mm->mm_rb;
329 : : int i = 0, j, bug = 0;
330 : : struct rb_node *nd, *pn = NULL;
331 : : unsigned long prev = 0, pend = 0;
332 : :
333 : : for (nd = rb_first(root); nd; nd = rb_next(nd)) {
334 : : struct vm_area_struct *vma;
335 : : vma = rb_entry(nd, struct vm_area_struct, vm_rb);
336 : : if (vma->vm_start < prev) {
337 : : pr_emerg("vm_start %lx < prev %lx\n",
338 : : vma->vm_start, prev);
339 : : bug = 1;
340 : : }
341 : : if (vma->vm_start < pend) {
342 : : pr_emerg("vm_start %lx < pend %lx\n",
343 : : vma->vm_start, pend);
344 : : bug = 1;
345 : : }
346 : : if (vma->vm_start > vma->vm_end) {
347 : : pr_emerg("vm_start %lx > vm_end %lx\n",
348 : : vma->vm_start, vma->vm_end);
349 : : bug = 1;
350 : : }
351 : : spin_lock(&mm->page_table_lock);
352 : : if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
353 : : pr_emerg("free gap %lx, correct %lx\n",
354 : : vma->rb_subtree_gap,
355 : : vma_compute_subtree_gap(vma));
356 : : bug = 1;
357 : : }
358 : : spin_unlock(&mm->page_table_lock);
359 : : i++;
360 : : pn = nd;
361 : : prev = vma->vm_start;
362 : : pend = vma->vm_end;
363 : : }
364 : : j = 0;
365 : : for (nd = pn; nd; nd = rb_prev(nd))
366 : : j++;
367 : : if (i != j) {
368 : : pr_emerg("backwards %d, forwards %d\n", j, i);
369 : : bug = 1;
370 : : }
371 : : return bug ? -1 : i;
372 : : }
373 : :
374 : : static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
375 : : {
376 : : struct rb_node *nd;
377 : :
378 : : for (nd = rb_first(root); nd; nd = rb_next(nd)) {
379 : : struct vm_area_struct *vma;
380 : : vma = rb_entry(nd, struct vm_area_struct, vm_rb);
381 : : VM_BUG_ON_VMA(vma != ignore &&
382 : : vma->rb_subtree_gap != vma_compute_subtree_gap(vma),
383 : : vma);
384 : : }
385 : : }
386 : :
387 : : static void validate_mm(struct mm_struct *mm)
388 : : {
389 : : int bug = 0;
390 : : int i = 0;
391 : : unsigned long highest_address = 0;
392 : : struct vm_area_struct *vma = mm->mmap;
393 : :
394 : : while (vma) {
395 : : struct anon_vma *anon_vma = vma->anon_vma;
396 : : struct anon_vma_chain *avc;
397 : :
398 : : if (anon_vma) {
399 : : anon_vma_lock_read(anon_vma);
400 : : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
401 : : anon_vma_interval_tree_verify(avc);
402 : : anon_vma_unlock_read(anon_vma);
403 : : }
404 : :
405 : : highest_address = vm_end_gap(vma);
406 : : vma = vma->vm_next;
407 : : i++;
408 : : }
409 : : if (i != mm->map_count) {
410 : : pr_emerg("map_count %d vm_next %d\n", mm->map_count, i);
411 : : bug = 1;
412 : : }
413 : : if (highest_address != mm->highest_vm_end) {
414 : : pr_emerg("mm->highest_vm_end %lx, found %lx\n",
415 : : mm->highest_vm_end, highest_address);
416 : : bug = 1;
417 : : }
418 : : i = browse_rb(mm);
419 : : if (i != mm->map_count) {
420 : : if (i != -1)
421 : : pr_emerg("map_count %d rb %d\n", mm->map_count, i);
422 : : bug = 1;
423 : : }
424 : : VM_BUG_ON_MM(bug, mm);
425 : : }
426 : : #else
427 : : #define validate_mm_rb(root, ignore) do { } while (0)
428 : : #define validate_mm(mm) do { } while (0)
429 : : #endif
430 : :
431 [ + + + + : 27811097 : RB_DECLARE_CALLBACKS_MAX(static, vma_gap_callbacks,
+ + + + +
+ ]
432 : : struct vm_area_struct, vm_rb,
433 : : unsigned long, rb_subtree_gap, vma_compute_gap)
434 : :
435 : : /*
436 : : * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
437 : : * vma->vm_prev->vm_end values changed, without modifying the vma's position
438 : : * in the rbtree.
439 : : */
440 : 3486180 : static void vma_gap_update(struct vm_area_struct *vma)
441 : : {
442 : : /*
443 : : * As it turns out, RB_DECLARE_CALLBACKS_MAX() already created
444 : : * a callback function that does exactly what we want.
445 : : */
446 : 3486180 : vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
447 : 1376942 : }
448 : :
449 : 2091241 : static inline void vma_rb_insert(struct vm_area_struct *vma,
450 : : struct rb_root *root)
451 : : {
452 : : /* All rb_subtree_gap values must be consistent prior to insertion */
453 : 2091241 : validate_mm_rb(root, NULL);
454 : :
455 : 2091241 : rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
456 : : }
457 : :
458 : 274534 : static void __vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
459 : : {
460 : : /*
461 : : * Note rb_erase_augmented is a fairly large inline function,
462 : : * so make sure we instantiate it only once with our desired
463 : : * augmented rbtree callbacks.
464 : : */
465 [ + + ]: 274534 : rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
466 : 274534 : }
467 : :
468 : 0 : static __always_inline void vma_rb_erase_ignore(struct vm_area_struct *vma,
469 : : struct rb_root *root,
470 : : struct vm_area_struct *ignore)
471 : : {
472 : : /*
473 : : * All rb_subtree_gap values must be consistent prior to erase,
474 : : * with the possible exception of the "next" vma being erased if
475 : : * next->vm_start was reduced.
476 : : */
477 : 0 : validate_mm_rb(root, ignore);
478 : :
479 : 0 : __vma_rb_erase(vma, root);
480 : : }
481 : :
482 : 274534 : static __always_inline void vma_rb_erase(struct vm_area_struct *vma,
483 : : struct rb_root *root)
484 : : {
485 : : /*
486 : : * All rb_subtree_gap values must be consistent prior to erase,
487 : : * with the possible exception of the vma being erased.
488 : : */
489 : 274534 : validate_mm_rb(root, vma);
490 : :
491 : 274534 : __vma_rb_erase(vma, root);
492 : : }
493 : :
494 : : /*
495 : : * vma has some anon_vma assigned, and is already inserted on that
496 : : * anon_vma's interval trees.
497 : : *
498 : : * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
499 : : * vma must be removed from the anon_vma's interval trees using
500 : : * anon_vma_interval_tree_pre_update_vma().
501 : : *
502 : : * After the update, the vma will be reinserted using
503 : : * anon_vma_interval_tree_post_update_vma().
504 : : *
505 : : * The entire update must be protected by exclusive mmap_sem and by
506 : : * the root anon_vma's mutex.
507 : : */
508 : : static inline void
509 : 176216 : anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma)
510 : : {
511 : 176216 : struct anon_vma_chain *avc;
512 : :
513 [ + + ]: 351135 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
514 : 174919 : anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root);
515 : 176216 : }
516 : :
517 : : static inline void
518 : 176216 : anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
519 : : {
520 : 176216 : struct anon_vma_chain *avc;
521 : :
522 [ + + ]: 351135 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
523 : 174919 : anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
524 : 176216 : }
525 : :
526 : 1331014 : static int find_vma_links(struct mm_struct *mm, unsigned long addr,
527 : : unsigned long end, struct vm_area_struct **pprev,
528 : : struct rb_node ***rb_link, struct rb_node **rb_parent)
529 : : {
530 : 1331014 : struct rb_node **__rb_link, *__rb_parent, *rb_prev;
531 : :
532 : 1331014 : __rb_link = &mm->mm_rb.rb_node;
533 : 1331014 : rb_prev = __rb_parent = NULL;
534 : :
535 [ - - + + : 8860402 : while (*__rb_link) {
+ + + + +
+ ]
536 : 7739913 : struct vm_area_struct *vma_tmp;
537 : :
538 : 7739913 : __rb_parent = *__rb_link;
539 : 7739913 : vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
540 : :
541 [ - - + + : 7739913 : if (vma_tmp->vm_end > addr) {
+ + + + +
+ ]
542 : : /* Fail if an existing vma overlaps the area */
543 [ - - + - : 4923038 : if (vma_tmp->vm_start < end)
+ - + + +
- ]
544 : : return -ENOMEM;
545 : 4712513 : __rb_link = &__rb_parent->rb_left;
546 : : } else {
547 : 2816875 : rb_prev = __rb_parent;
548 : 2816875 : __rb_link = &__rb_parent->rb_right;
549 : : }
550 : : }
551 : :
552 : 1120489 : *pprev = NULL;
553 [ - - + + : 1120489 : if (rb_prev)
+ - + + +
- ]
554 : 1084495 : *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
555 : : *rb_link = __rb_link;
556 : : *rb_parent = __rb_parent;
557 : : return 0;
558 : : }
559 : :
560 : 0 : static unsigned long count_vma_pages_range(struct mm_struct *mm,
561 : : unsigned long addr, unsigned long end)
562 : : {
563 : 0 : unsigned long nr_pages = 0;
564 : 0 : struct vm_area_struct *vma;
565 : :
566 : : /* Find first overlaping mapping */
567 : 0 : vma = find_vma_intersection(mm, addr, end);
568 [ # # ]: 0 : if (!vma)
569 : : return 0;
570 : :
571 : 0 : nr_pages = (min(end, vma->vm_end) -
572 : 0 : max(addr, vma->vm_start)) >> PAGE_SHIFT;
573 : :
574 : : /* Iterate over the rest of the overlaps */
575 [ # # ]: 0 : for (vma = vma->vm_next; vma; vma = vma->vm_next) {
576 : 0 : unsigned long overlap_len;
577 : :
578 [ # # ]: 0 : if (vma->vm_start > end)
579 : : break;
580 : :
581 : 0 : overlap_len = min(end, vma->vm_end) - vma->vm_start;
582 : 0 : nr_pages += overlap_len >> PAGE_SHIFT;
583 : : }
584 : :
585 : : return nr_pages;
586 : : }
587 : :
588 : 2091241 : void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
589 : : struct rb_node **rb_link, struct rb_node *rb_parent)
590 : : {
591 : : /* Update tracking information for the gap following the new vma. */
592 [ + + ]: 2091241 : if (vma->vm_next)
593 : 1033849 : vma_gap_update(vma->vm_next);
594 : : else
595 : 1057392 : mm->highest_vm_end = vm_end_gap(vma);
596 : :
597 : : /*
598 : : * vma->vm_prev wasn't known when we followed the rbtree to find the
599 : : * correct insertion point for that vma. As a result, we could not
600 : : * update the vma vm_rb parents rb_subtree_gap values on the way down.
601 : : * So, we first insert the vma with a zero rb_subtree_gap value
602 : : * (to be consistent with what we did on the way down), and then
603 : : * immediately update the gap to the correct value. Finally we
604 : : * rebalance the rbtree after all augmented values have been set.
605 : : */
606 : 2091241 : rb_link_node(&vma->vm_rb, rb_parent, rb_link);
607 : 2091241 : vma->rb_subtree_gap = 0;
608 : 2091241 : vma_gap_update(vma);
609 : 2091241 : vma_rb_insert(vma, &mm->mm_rb);
610 : 2091241 : }
611 : :
612 : 1068360 : static void __vma_link_file(struct vm_area_struct *vma)
613 : : {
614 : 1068360 : struct file *file;
615 : :
616 : 1068360 : file = vma->vm_file;
617 [ + + ]: 1068360 : if (file) {
618 : 920724 : struct address_space *mapping = file->f_mapping;
619 : :
620 [ + + ]: 920724 : if (vma->vm_flags & VM_DENYWRITE)
621 : 215880 : atomic_dec(&file_inode(file)->i_writecount);
622 [ + + ]: 920724 : if (vma->vm_flags & VM_SHARED)
623 : 84 : atomic_inc(&mapping->i_mmap_writable);
624 : :
625 : 920724 : flush_dcache_mmap_lock(mapping);
626 : 920724 : vma_interval_tree_insert(vma, &mapping->i_mmap);
627 : 920724 : flush_dcache_mmap_unlock(mapping);
628 : : }
629 : 1068360 : }
630 : :
631 : : static void
632 : 1069843 : __vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
633 : : struct vm_area_struct *prev, struct rb_node **rb_link,
634 : : struct rb_node *rb_parent)
635 : : {
636 : 1069843 : __vma_link_list(mm, vma, prev);
637 : 1069843 : __vma_link_rb(mm, vma, rb_link, rb_parent);
638 : : }
639 : :
640 : 659259 : static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
641 : : struct vm_area_struct *prev, struct rb_node **rb_link,
642 : : struct rb_node *rb_parent)
643 : : {
644 : 659259 : struct address_space *mapping = NULL;
645 : :
646 [ + + ]: 659259 : if (vma->vm_file) {
647 : 511623 : mapping = vma->vm_file->f_mapping;
648 : 511623 : i_mmap_lock_write(mapping);
649 : : }
650 : :
651 : 659259 : __vma_link(mm, vma, prev, rb_link, rb_parent);
652 : 659259 : __vma_link_file(vma);
653 : :
654 [ + + ]: 659259 : if (mapping)
655 : 511623 : i_mmap_unlock_write(mapping);
656 : :
657 : 659259 : mm->map_count++;
658 : 659259 : validate_mm(mm);
659 : 659259 : }
660 : :
661 : : /*
662 : : * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
663 : : * mm's list and rbtree. It has already been inserted into the interval tree.
664 : : */
665 : 410584 : static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
666 : : {
667 : 410584 : struct vm_area_struct *prev;
668 : 410584 : struct rb_node **rb_link, *rb_parent;
669 : :
670 [ - + ]: 821168 : if (find_vma_links(mm, vma->vm_start, vma->vm_end,
671 : : &prev, &rb_link, &rb_parent))
672 : 0 : BUG();
673 : 410584 : __vma_link(mm, vma, prev, rb_link, rb_parent);
674 : 410584 : mm->map_count++;
675 : 410584 : }
676 : :
677 : 0 : static __always_inline void __vma_unlink_common(struct mm_struct *mm,
678 : : struct vm_area_struct *vma,
679 : : struct vm_area_struct *ignore)
680 : : {
681 : 0 : vma_rb_erase_ignore(vma, &mm->mm_rb, ignore);
682 : 0 : __vma_unlink_list(mm, vma);
683 : : /* Kill the cache */
684 : 0 : vmacache_invalidate(mm);
685 : : }
686 : :
687 : : /*
688 : : * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
689 : : * is already present in an i_mmap tree without adjusting the tree.
690 : : * The following helper function should be used when such adjustments
691 : : * are necessary. The "insert" vma (if any) is to be inserted
692 : : * before we drop the necessary locks.
693 : : */
694 : 498521 : int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
695 : : unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert,
696 : : struct vm_area_struct *expand)
697 : : {
698 : 498521 : struct mm_struct *mm = vma->vm_mm;
699 : 498521 : struct vm_area_struct *next = vma->vm_next, *orig_vma = vma;
700 : 498521 : struct address_space *mapping = NULL;
701 : 498521 : struct rb_root_cached *root = NULL;
702 : 498521 : struct anon_vma *anon_vma = NULL;
703 : 498521 : struct file *file = vma->vm_file;
704 : 498521 : bool start_changed = false, end_changed = false;
705 : 498521 : long adjust_next = 0;
706 : 498521 : int remove_next = 0;
707 : :
708 [ + + ]: 498521 : if (next && !insert) {
709 : 51943 : struct vm_area_struct *exporter = NULL, *importer = NULL;
710 : :
711 [ - + ]: 51943 : if (end >= next->vm_end) {
712 : : /*
713 : : * vma expands, overlapping all the next, and
714 : : * perhaps the one after too (mprotect case 6).
715 : : * The only other cases that gets here are
716 : : * case 1, case 7 and case 8.
717 : : */
718 [ # # ]: 0 : if (next == expand) {
719 : : /*
720 : : * The only case where we don't expand "vma"
721 : : * and we expand "next" instead is case 8.
722 : : */
723 : : VM_WARN_ON(end != next->vm_end);
724 : : /*
725 : : * remove_next == 3 means we're
726 : : * removing "vma" and that to do so we
727 : : * swapped "vma" and "next".
728 : : */
729 : : remove_next = 3;
730 : : VM_WARN_ON(file != next->vm_file);
731 : : swap(vma, next);
732 : : } else {
733 : 0 : VM_WARN_ON(expand != vma);
734 : : /*
735 : : * case 1, 6, 7, remove_next == 2 is case 6,
736 : : * remove_next == 1 is case 1 or 7.
737 : : */
738 [ # # ]: 0 : remove_next = 1 + (end > next->vm_end);
739 : : VM_WARN_ON(remove_next == 2 &&
740 : : end != next->vm_next->vm_end);
741 : : /* trim end to next, for case 6 first pass */
742 : : end = next->vm_end;
743 : : }
744 : :
745 : 0 : exporter = next;
746 : 0 : importer = vma;
747 : :
748 : : /*
749 : : * If next doesn't have anon_vma, import from vma after
750 : : * next, if the vma overlaps with it.
751 : : */
752 [ # # # # ]: 0 : if (remove_next == 2 && !next->anon_vma)
753 : 0 : exporter = next->vm_next;
754 : :
755 [ + + ]: 51943 : } else if (end > next->vm_start) {
756 : : /*
757 : : * vma expands, overlapping part of the next:
758 : : * mprotect case 5 shifting the boundary up.
759 : : */
760 : 1255 : adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
761 : 1255 : exporter = next;
762 : 1255 : importer = vma;
763 : 1255 : VM_WARN_ON(expand != importer);
764 [ + + ]: 50688 : } else if (end < vma->vm_end) {
765 : : /*
766 : : * vma shrinks, and !insert tells it's not
767 : : * split_vma inserting another: so it must be
768 : : * mprotect case 4 shifting the boundary down.
769 : : */
770 : 42 : adjust_next = -((vma->vm_end - end) >> PAGE_SHIFT);
771 : 42 : exporter = vma;
772 : 42 : importer = next;
773 : 51943 : VM_WARN_ON(expand != importer);
774 : : }
775 : :
776 : : /*
777 : : * Easily overlooked: when mprotect shifts the boundary,
778 : : * make sure the expanding vma has anon_vma set if the
779 : : * shrinking vma had, to cover any anon pages imported.
780 : : */
781 [ + + + - : 51943 : if (exporter && exporter->anon_vma && !importer->anon_vma) {
- - ]
782 : 0 : int error;
783 : :
784 : 0 : importer->anon_vma = exporter->anon_vma;
785 : 0 : error = anon_vma_clone(importer, exporter);
786 [ # # ]: 0 : if (error)
787 : : return error;
788 : : }
789 : : }
790 : 498521 : again:
791 [ + + ]: 498521 : vma_adjust_trans_huge(orig_vma, start, end, adjust_next);
792 : :
793 [ + + ]: 498521 : if (file) {
794 : 440538 : mapping = file->f_mapping;
795 : 440538 : root = &mapping->i_mmap;
796 : 440538 : uprobe_munmap(vma, vma->vm_start, vma->vm_end);
797 : :
798 [ - + ]: 440538 : if (adjust_next)
799 : 0 : uprobe_munmap(next, next->vm_start, next->vm_end);
800 : :
801 : 440538 : i_mmap_lock_write(mapping);
802 [ + + ]: 440538 : if (insert) {
803 : : /*
804 : : * Put into interval tree now, so instantiated pages
805 : : * are visible to arm/parisc __flush_dcache_page
806 : : * throughout; but we cannot insert into address
807 : : * space until vma start or end is updated.
808 : : */
809 : 409101 : __vma_link_file(insert);
810 : : }
811 : : }
812 : :
813 : 498521 : anon_vma = vma->anon_vma;
814 [ + + ]: 498521 : if (!anon_vma && adjust_next)
815 : 42 : anon_vma = next->anon_vma;
816 [ + + ]: 498521 : if (anon_vma) {
817 : 156922 : VM_WARN_ON(adjust_next && next->anon_vma &&
818 : : anon_vma != next->anon_vma);
819 : 156922 : anon_vma_lock_write(anon_vma);
820 : 156922 : anon_vma_interval_tree_pre_update_vma(vma);
821 [ + + ]: 156922 : if (adjust_next)
822 : 1297 : anon_vma_interval_tree_pre_update_vma(next);
823 : : }
824 : :
825 [ + + ]: 498521 : if (root) {
826 : 440538 : flush_dcache_mmap_lock(mapping);
827 : 440538 : vma_interval_tree_remove(vma, root);
828 [ - + ]: 440538 : if (adjust_next)
829 : 0 : vma_interval_tree_remove(next, root);
830 : : }
831 : :
832 [ + + ]: 498521 : if (start != vma->vm_start) {
833 : 247689 : vma->vm_start = start;
834 : 247689 : start_changed = true;
835 : : }
836 [ + + ]: 498521 : if (end != vma->vm_end) {
837 : 250832 : vma->vm_end = end;
838 : 250832 : end_changed = true;
839 : : }
840 : 498521 : vma->vm_pgoff = pgoff;
841 [ + + ]: 498521 : if (adjust_next) {
842 : 1297 : next->vm_start += adjust_next << PAGE_SHIFT;
843 : 1297 : next->vm_pgoff += adjust_next;
844 : : }
845 : :
846 [ + + ]: 498521 : if (root) {
847 [ - + ]: 440538 : if (adjust_next)
848 : 0 : vma_interval_tree_insert(next, root);
849 : 440538 : vma_interval_tree_insert(vma, root);
850 : 440538 : flush_dcache_mmap_unlock(mapping);
851 : : }
852 : :
853 [ - + ]: 498521 : if (remove_next) {
854 : : /*
855 : : * vma_merge has merged next into vma, and needs
856 : : * us to remove next before dropping the locks.
857 : : */
858 [ # # ]: 0 : if (remove_next != 3)
859 : 0 : __vma_unlink_common(mm, next, next);
860 : : else
861 : : /*
862 : : * vma is not before next if they've been
863 : : * swapped.
864 : : *
865 : : * pre-swap() next->vm_start was reduced so
866 : : * tell validate_mm_rb to ignore pre-swap()
867 : : * "next" (which is stored in post-swap()
868 : : * "vma").
869 : : */
870 : 0 : __vma_unlink_common(mm, next, vma);
871 [ # # ]: 0 : if (file)
872 : 0 : __remove_shared_vm_struct(next, file, mapping);
873 [ + + ]: 498521 : } else if (insert) {
874 : : /*
875 : : * split_vma has split insert from vma, and needs
876 : : * us to insert it before dropping the locks
877 : : * (it may either follow vma or precede it).
878 : : */
879 : 410584 : __insert_vm_struct(mm, insert);
880 : : } else {
881 [ + + ]: 87937 : if (start_changed)
882 : 68224 : vma_gap_update(vma);
883 [ + + ]: 87937 : if (end_changed) {
884 [ + + ]: 19713 : if (!next)
885 : 17997 : mm->highest_vm_end = vm_end_gap(vma);
886 [ + + ]: 1716 : else if (!adjust_next)
887 : 419 : vma_gap_update(next);
888 : : }
889 : : }
890 : :
891 [ + + ]: 498521 : if (anon_vma) {
892 : 156922 : anon_vma_interval_tree_post_update_vma(vma);
893 [ + + ]: 156922 : if (adjust_next)
894 : 1297 : anon_vma_interval_tree_post_update_vma(next);
895 : 156922 : anon_vma_unlock_write(anon_vma);
896 : : }
897 [ + + ]: 498521 : if (mapping)
898 : 440538 : i_mmap_unlock_write(mapping);
899 : :
900 [ + + ]: 498521 : if (root) {
901 : 440538 : uprobe_mmap(vma);
902 : :
903 [ - + ]: 440538 : if (adjust_next)
904 : 0 : uprobe_mmap(next);
905 : : }
906 : :
907 [ - + ]: 498521 : if (remove_next) {
908 [ # # ]: 0 : if (file) {
909 : 0 : uprobe_munmap(next, next->vm_start, next->vm_end);
910 : 0 : fput(file);
911 : : }
912 [ # # ]: 0 : if (next->anon_vma)
913 : 0 : anon_vma_merge(vma, next);
914 : 0 : mm->map_count--;
915 [ # # ]: 0 : mpol_put(vma_policy(next));
916 : 0 : vm_area_free(next);
917 : : /*
918 : : * In mprotect's case 6 (see comments on vma_merge),
919 : : * we must remove another next too. It would clutter
920 : : * up the code too much to do both in one go.
921 : : */
922 [ # # ]: 0 : if (remove_next != 3) {
923 : : /*
924 : : * If "next" was removed and vma->vm_end was
925 : : * expanded (up) over it, in turn
926 : : * "next->vm_prev->vm_end" changed and the
927 : : * "vma->vm_next" gap must be updated.
928 : : */
929 : 0 : next = vma->vm_next;
930 : : } else {
931 : : /*
932 : : * For the scope of the comment "next" and
933 : : * "vma" considered pre-swap(): if "vma" was
934 : : * removed, next->vm_start was expanded (down)
935 : : * over it and the "next" gap must be updated.
936 : : * Because of the swap() the post-swap() "vma"
937 : : * actually points to pre-swap() "next"
938 : : * (post-swap() "next" as opposed is now a
939 : : * dangling pointer).
940 : : */
941 : : next = vma;
942 : : }
943 [ # # ]: 0 : if (remove_next == 2) {
944 : 0 : remove_next = 1;
945 : 0 : end = next->vm_end;
946 : 0 : goto again;
947 : : }
948 [ # # ]: 0 : else if (next)
949 : 0 : vma_gap_update(next);
950 : : else {
951 : : /*
952 : : * If remove_next == 2 we obviously can't
953 : : * reach this path.
954 : : *
955 : : * If remove_next == 3 we can't reach this
956 : : * path because pre-swap() next is always not
957 : : * NULL. pre-swap() "next" is not being
958 : : * removed and its next->vm_end is not altered
959 : : * (and furthermore "end" already matches
960 : : * next->vm_end in remove_next == 3).
961 : : *
962 : : * We reach this only in the remove_next == 1
963 : : * case if the "next" vma that was removed was
964 : : * the highest vma of the mm. However in such
965 : : * case next->vm_end == "end" and the extended
966 : : * "vma" has vma->vm_end == next->vm_end so
967 : : * mm->highest_vm_end doesn't need any update
968 : : * in remove_next == 1 case.
969 : : */
970 : 498521 : VM_WARN_ON(mm->highest_vm_end != vm_end_gap(vma));
971 : : }
972 : : }
973 [ + + ]: 498521 : if (insert && file)
974 : 409101 : uprobe_mmap(insert);
975 : :
976 : : validate_mm(mm);
977 : :
978 : : return 0;
979 : : }
980 : :
981 : : /*
982 : : * If the vma has a ->close operation then the driver probably needs to release
983 : : * per-vma resources, so we don't attempt to merge those.
984 : : */
985 : 903061 : static inline int is_mergeable_vma(struct vm_area_struct *vma,
986 : : struct file *file, unsigned long vm_flags,
987 : : struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
988 : : {
989 : : /*
990 : : * VM_SOFTDIRTY should not prevent from VMA merging, if we
991 : : * match the flags but dirty bit -- the caller should mark
992 : : * merged VMA as dirty. If dirty bit won't be excluded from
993 : : * comparison, we increase pressure on the memory system forcing
994 : : * the kernel to generate new VMAs when old one could be
995 : : * extended instead.
996 : : */
997 : 903061 : if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY)
998 : : return 0;
999 [ + + + + ]: 233213 : if (vma->vm_file != file)
1000 : : return 0;
1001 [ - + - - : 51983 : if (vma->vm_ops && vma->vm_ops->close)
+ + + - ]
1002 : : return 0;
1003 [ + - + - ]: 51983 : if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
1004 : : return 0;
1005 : 51983 : return 1;
1006 : : }
1007 : :
1008 : 51983 : static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
1009 : : struct anon_vma *anon_vma2,
1010 : : struct vm_area_struct *vma)
1011 : : {
1012 : : /*
1013 : : * The list_is_singular() test is to avoid merging VMA cloned from
1014 : : * parents. This can improve scalability caused by anon_vma lock.
1015 : : */
1016 [ + - + - ]: 51983 : if ((!anon_vma1 || !anon_vma2) && (!vma ||
1017 [ + + + + ]: 51983 : list_is_singular(&vma->anon_vma_chain)))
1018 : : return 1;
1019 : 31532 : return anon_vma1 == anon_vma2;
1020 : : }
1021 : :
1022 : : /*
1023 : : * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
1024 : : * in front of (at a lower virtual address and file offset than) the vma.
1025 : : *
1026 : : * We cannot merge two vmas if they have differently assigned (non-NULL)
1027 : : * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
1028 : : *
1029 : : * We don't check here for the merged mmap wrapping around the end of pagecache
1030 : : * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
1031 : : * wrap, nor mmaps which cover the final page at index -1UL.
1032 : : */
1033 : : static int
1034 : 469794 : can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
1035 : : struct anon_vma *anon_vma, struct file *file,
1036 : : pgoff_t vm_pgoff,
1037 : : struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
1038 : : {
1039 [ + + + - ]: 501269 : if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
1040 [ + - ]: 50269 : is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
1041 [ + - ]: 50269 : if (vma->vm_pgoff == vm_pgoff)
1042 : 50269 : return 1;
1043 : : }
1044 : : return 0;
1045 : : }
1046 : :
1047 : : /*
1048 : : * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
1049 : : * beyond (at a higher virtual address and file offset than) the vma.
1050 : : *
1051 : : * We cannot merge two vmas if they have differently assigned (non-NULL)
1052 : : * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
1053 : : */
1054 : : static int
1055 : 433267 : can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
1056 : : struct anon_vma *anon_vma, struct file *file,
1057 : : pgoff_t vm_pgoff,
1058 : : struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
1059 : : {
1060 [ + + + + ]: 433324 : if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
1061 [ + - ]: 1714 : is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
1062 : 1674 : pgoff_t vm_pglen;
1063 [ + - ]: 1674 : vm_pglen = vma_pages(vma);
1064 [ + - ]: 1674 : if (vma->vm_pgoff + vm_pglen == vm_pgoff)
1065 : 1674 : return 1;
1066 : : }
1067 : : return 0;
1068 : : }
1069 : :
1070 : : /*
1071 : : * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
1072 : : * whether that can be merged with its predecessor or its successor.
1073 : : * Or both (it neatly fills a hole).
1074 : : *
1075 : : * In most cases - when called for mmap, brk or mremap - [addr,end) is
1076 : : * certain not to be mapped by the time vma_merge is called; but when
1077 : : * called for mprotect, it is certain to be already mapped (either at
1078 : : * an offset within prev, or at the start of next), and the flags of
1079 : : * this area are about to be changed to vm_flags - and the no-change
1080 : : * case has already been eliminated.
1081 : : *
1082 : : * The following mprotect cases have to be considered, where AAAA is
1083 : : * the area passed down from mprotect_fixup, never extending beyond one
1084 : : * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
1085 : : *
1086 : : * AAAA AAAA AAAA
1087 : : * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN
1088 : : * cannot merge might become might become
1089 : : * PPNNNNNNNNNN PPPPPPPPPPNN
1090 : : * mmap, brk or case 4 below case 5 below
1091 : : * mremap move:
1092 : : * AAAA AAAA
1093 : : * PPPP NNNN PPPPNNNNXXXX
1094 : : * might become might become
1095 : : * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or
1096 : : * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or
1097 : : * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8
1098 : : *
1099 : : * It is important for case 8 that the vma NNNN overlapping the
1100 : : * region AAAA is never going to extended over XXXX. Instead XXXX must
1101 : : * be extended in region AAAA and NNNN must be removed. This way in
1102 : : * all cases where vma_merge succeeds, the moment vma_adjust drops the
1103 : : * rmap_locks, the properties of the merged vma will be already
1104 : : * correct for the whole merged range. Some of those properties like
1105 : : * vm_page_prot/vm_flags may be accessed by rmap_walks and they must
1106 : : * be correct for the whole merged range immediately after the
1107 : : * rmap_locks are released. Otherwise if XXXX would be removed and
1108 : : * NNNN would be extended over the XXXX range, remove_migration_ptes
1109 : : * or other rmap walkers (if working on addresses beyond the "end"
1110 : : * parameter) may establish ptes with the wrong permissions of NNNN
1111 : : * instead of the right permissions of XXXX.
1112 : : */
1113 : 788482 : struct vm_area_struct *vma_merge(struct mm_struct *mm,
1114 : : struct vm_area_struct *prev, unsigned long addr,
1115 : : unsigned long end, unsigned long vm_flags,
1116 : : struct anon_vma *anon_vma, struct file *file,
1117 : : pgoff_t pgoff, struct mempolicy *policy,
1118 : : struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
1119 : : {
1120 : 788482 : pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
1121 : 788482 : struct vm_area_struct *area, *next;
1122 : 788482 : int err;
1123 : :
1124 : : /*
1125 : : * We later require that vma->vm_flags == vm_flags,
1126 : : * so this tests vma->vm_flags & VM_SPECIAL, too.
1127 : : */
1128 [ + - ]: 788482 : if (vm_flags & VM_SPECIAL)
1129 : : return NULL;
1130 : :
1131 [ + + ]: 788482 : if (prev)
1132 : 770485 : next = prev->vm_next;
1133 : : else
1134 : 17997 : next = mm->mmap;
1135 : 788482 : area = next;
1136 [ + - - + ]: 788482 : if (area && area->vm_end == end) /* cases 6, 7, 8 */
1137 : 0 : next = next->vm_next;
1138 : :
1139 : : /* verify some invariant that must be enforced by the caller */
1140 : 788482 : VM_WARN_ON(prev && addr <= prev->vm_start);
1141 : 788482 : VM_WARN_ON(area && end > area->vm_end);
1142 : 788482 : VM_WARN_ON(addr >= end);
1143 : :
1144 : : /*
1145 : : * Can it merge with the predecessor?
1146 : : */
1147 [ + + + + : 788482 : if (prev && prev->vm_end == addr &&
- - ]
1148 [ - + + + ]: 866534 : mpol_equal(vma_policy(prev), policy) &&
1149 : 433267 : can_vma_merge_after(prev, vm_flags,
1150 : : anon_vma, file, pgoff,
1151 : : vm_userfaultfd_ctx)) {
1152 : : /*
1153 : : * OK, it can. Can we now merge in the successor as well?
1154 : : */
1155 [ + - + + : 1674 : if (next && end == next->vm_start &&
- - ]
1156 [ - + - + ]: 34 : mpol_equal(policy, vma_policy(next)) &&
1157 : 17 : can_vma_merge_before(next, vm_flags,
1158 : : anon_vma, file,
1159 : : pgoff+pglen,
1160 [ # # ]: 0 : vm_userfaultfd_ctx) &&
1161 [ # # ]: 0 : is_mergeable_anon_vma(prev->anon_vma,
1162 : : next->anon_vma, NULL)) {
1163 : : /* cases 1, 6 */
1164 : 0 : err = __vma_adjust(prev, prev->vm_start,
1165 : : next->vm_end, prev->vm_pgoff, NULL,
1166 : : prev);
1167 : : } else /* cases 2, 5, 7 */
1168 : 1674 : err = __vma_adjust(prev, prev->vm_start,
1169 : : end, prev->vm_pgoff, NULL, prev);
1170 [ + - ]: 1674 : if (err)
1171 : : return NULL;
1172 : 1674 : khugepaged_enter_vma_merge(prev, vm_flags);
1173 : 1674 : return prev;
1174 : : }
1175 : :
1176 : : /*
1177 : : * Can this new request be merged in front of next?
1178 : : */
1179 [ + - + + : 786808 : if (next && end == next->vm_start &&
- - ]
1180 [ - + + + ]: 939554 : mpol_equal(policy, vma_policy(next)) &&
1181 : 469777 : can_vma_merge_before(next, vm_flags,
1182 : : anon_vma, file, pgoff+pglen,
1183 : : vm_userfaultfd_ctx)) {
1184 [ + - + + ]: 50269 : if (prev && addr < prev->vm_end) /* case 4 */
1185 : 42 : err = __vma_adjust(prev, prev->vm_start,
1186 : : addr, prev->vm_pgoff, NULL, next);
1187 : : else { /* cases 3, 8 */
1188 : 50227 : err = __vma_adjust(area, addr, next->vm_end,
1189 : 50227 : next->vm_pgoff - pglen, NULL, next);
1190 : : /*
1191 : : * In case 3 area is already equal to next and
1192 : : * this is a noop, but in case 8 "area" has
1193 : : * been removed and next was expanded over it.
1194 : : */
1195 : 50227 : area = next;
1196 : : }
1197 [ + - ]: 50269 : if (err)
1198 : : return NULL;
1199 : 50269 : khugepaged_enter_vma_merge(area, vm_flags);
1200 : 50269 : return area;
1201 : : }
1202 : :
1203 : : return NULL;
1204 : : }
1205 : :
1206 : : /*
1207 : : * Rough compatbility check to quickly see if it's even worth looking
1208 : : * at sharing an anon_vma.
1209 : : *
1210 : : * They need to have the same vm_file, and the flags can only differ
1211 : : * in things that mprotect may change.
1212 : : *
1213 : : * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1214 : : * we can merge the two vma's. For example, we refuse to merge a vma if
1215 : : * there is a vm_ops->close() function, because that indicates that the
1216 : : * driver is doing some kind of reference counting. But that doesn't
1217 : : * really matter for the anon_vma sharing case.
1218 : : */
1219 : 384002 : static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
1220 : : {
1221 [ # # ]: 0 : return a->vm_end == b->vm_start &&
1222 [ - + ]: 248931 : mpol_equal(vma_policy(a), vma_policy(b)) &&
1223 [ + + ]: 248931 : a->vm_file == b->vm_file &&
1224 [ + + + + ]: 507077 : !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) &&
1225 [ - + ]: 141 : b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
1226 : : }
1227 : :
1228 : : /*
1229 : : * Do some basic sanity checking to see if we can re-use the anon_vma
1230 : : * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1231 : : * the same as 'old', the other will be the new one that is trying
1232 : : * to share the anon_vma.
1233 : : *
1234 : : * NOTE! This runs with mm_sem held for reading, so it is possible that
1235 : : * the anon_vma of 'old' is concurrently in the process of being set up
1236 : : * by another page fault trying to merge _that_. But that's ok: if it
1237 : : * is being set up, that automatically means that it will be a singleton
1238 : : * acceptable for merging, so we can do all of this optimistically. But
1239 : : * we do that READ_ONCE() to make sure that we never re-load the pointer.
1240 : : *
1241 : : * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1242 : : * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1243 : : * is to return an anon_vma that is "complex" due to having gone through
1244 : : * a fork).
1245 : : *
1246 : : * We also make sure that the two vma's are compatible (adjacent,
1247 : : * and with the same memory policies). That's all stable, even with just
1248 : : * a read lock on the mm_sem.
1249 : : */
1250 : 384002 : static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
1251 : : {
1252 [ + + ]: 384002 : if (anon_vma_compatible(a, b)) {
1253 [ + + ]: 141 : struct anon_vma *anon_vma = READ_ONCE(old->anon_vma);
1254 : :
1255 [ + + + - ]: 141 : if (anon_vma && list_is_singular(&old->anon_vma_chain))
1256 : 0 : return anon_vma;
1257 : : }
1258 : : return NULL;
1259 : : }
1260 : :
1261 : : /*
1262 : : * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1263 : : * neighbouring vmas for a suitable anon_vma, before it goes off
1264 : : * to allocate a new anon_vma. It checks because a repetitive
1265 : : * sequence of mprotects and faults may otherwise lead to distinct
1266 : : * anon_vmas being allocated, preventing vma merge in subsequent
1267 : : * mprotect.
1268 : : */
1269 : 209998 : struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
1270 : : {
1271 : 209998 : struct anon_vma *anon_vma = NULL;
1272 : :
1273 : : /* Try next first. */
1274 [ + + ]: 209998 : if (vma->vm_next) {
1275 : 192001 : anon_vma = reusable_anon_vma(vma->vm_next, vma, vma->vm_next);
1276 [ + - ]: 192001 : if (anon_vma)
1277 : : return anon_vma;
1278 : : }
1279 : :
1280 : : /* Try prev next. */
1281 [ + + ]: 209998 : if (vma->vm_prev)
1282 : 192001 : anon_vma = reusable_anon_vma(vma->vm_prev, vma->vm_prev, vma);
1283 : :
1284 : : /*
1285 : : * We might reach here with anon_vma == NULL if we can't find
1286 : : * any reusable anon_vma.
1287 : : * There's no absolute need to look only at touching neighbours:
1288 : : * we could search further afield for "compatible" anon_vmas.
1289 : : * But it would probably just be a waste of time searching,
1290 : : * or lead to too many vmas hanging off the same anon_vma.
1291 : : * We're trying to allow mprotect remerging later on,
1292 : : * not trying to minimize memory used for anon_vmas.
1293 : : */
1294 : : return anon_vma;
1295 : : }
1296 : :
1297 : : /*
1298 : : * If a hint addr is less than mmap_min_addr change hint to be as
1299 : : * low as possible but still greater than mmap_min_addr
1300 : : */
1301 : 277220 : static inline unsigned long round_hint_to_min(unsigned long hint)
1302 : : {
1303 : 277220 : hint &= PAGE_MASK;
1304 : 277237 : if (((void *)hint != NULL) &&
1305 [ - + ]: 17 : (hint < mmap_min_addr))
1306 : 0 : return PAGE_ALIGN(mmap_min_addr);
1307 : : return hint;
1308 : : }
1309 : :
1310 : 655914 : static inline int mlock_future_check(struct mm_struct *mm,
1311 : : unsigned long flags,
1312 : : unsigned long len)
1313 : : {
1314 : 655914 : unsigned long locked, lock_limit;
1315 : :
1316 : : /* mlock MCL_FUTURE? */
1317 [ - + ]: 655914 : if (flags & VM_LOCKED) {
1318 : 0 : locked = len >> PAGE_SHIFT;
1319 : 0 : locked += mm->locked_vm;
1320 [ # # ]: 0 : lock_limit = rlimit(RLIMIT_MEMLOCK);
1321 : 0 : lock_limit >>= PAGE_SHIFT;
1322 [ # # # # ]: 0 : if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1323 : 0 : return -EAGAIN;
1324 : : }
1325 : : return 0;
1326 : : }
1327 : :
1328 : 543060 : static inline u64 file_mmap_size_max(struct file *file, struct inode *inode)
1329 : : {
1330 : 543060 : if (S_ISREG(inode->i_mode))
1331 : : return MAX_LFS_FILESIZE;
1332 : :
1333 [ # # ]: 0 : if (S_ISBLK(inode->i_mode))
1334 : : return MAX_LFS_FILESIZE;
1335 : :
1336 [ # # ]: 0 : if (S_ISSOCK(inode->i_mode))
1337 : : return MAX_LFS_FILESIZE;
1338 : :
1339 : : /* Special "we do even unsigned file positions" case */
1340 [ # # ]: 0 : if (file->f_mode & FMODE_UNSIGNED_OFFSET)
1341 : 0 : return 0;
1342 : :
1343 : : /* Yes, random drivers might want more. But I'm tired of buggy drivers */
1344 : : return ULONG_MAX;
1345 : : }
1346 : :
1347 : 543060 : static inline bool file_mmap_ok(struct file *file, struct inode *inode,
1348 : : unsigned long pgoff, unsigned long len)
1349 : : {
1350 : 543060 : u64 maxsize = file_mmap_size_max(file, inode);
1351 : :
1352 [ + - ]: 543060 : if (maxsize && len > maxsize)
1353 : : return false;
1354 : 543060 : maxsize -= len;
1355 [ + - ]: 543060 : if (pgoff > maxsize >> PAGE_SHIFT)
1356 : : return false;
1357 : : return true;
1358 : : }
1359 : :
1360 : : /*
1361 : : * The caller must hold down_write(¤t->mm->mmap_sem).
1362 : : */
1363 : 613640 : unsigned long do_mmap(struct file *file, unsigned long addr,
1364 : : unsigned long len, unsigned long prot,
1365 : : unsigned long flags, vm_flags_t vm_flags,
1366 : : unsigned long pgoff, unsigned long *populate,
1367 : : struct list_head *uf)
1368 : : {
1369 [ + - ]: 613640 : struct mm_struct *mm = current->mm;
1370 : 613640 : int pkey = 0;
1371 : :
1372 : 613640 : *populate = 0;
1373 : :
1374 [ + - ]: 613640 : if (!len)
1375 : : return -EINVAL;
1376 : :
1377 : : /*
1378 : : * Does the application expect PROT_READ to imply PROT_EXEC?
1379 : : *
1380 : : * (the exception is when the underlying filesystem is noexec
1381 : : * mounted, in which case we dont add PROT_EXEC.)
1382 : : */
1383 [ + + - + ]: 613640 : if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
1384 [ # # # # ]: 0 : if (!(file && path_noexec(&file->f_path)))
1385 : 0 : prot |= PROT_EXEC;
1386 : :
1387 : : /* force arch specific MAP_FIXED handling in get_unmapped_area */
1388 [ + + ]: 613640 : if (flags & MAP_FIXED_NOREPLACE)
1389 : 53991 : flags |= MAP_FIXED;
1390 : :
1391 [ + + ]: 613640 : if (!(flags & MAP_FIXED))
1392 [ + + ]: 277220 : addr = round_hint_to_min(addr);
1393 : :
1394 : : /* Careful about overflows.. */
1395 : 613640 : len = PAGE_ALIGN(len);
1396 [ + - ]: 613640 : if (!len)
1397 : : return -ENOMEM;
1398 : :
1399 : : /* offset overflow? */
1400 [ + - ]: 613640 : if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
1401 : : return -EOVERFLOW;
1402 : :
1403 : : /* Too many mappings? */
1404 [ + - ]: 613640 : if (mm->map_count > sysctl_max_map_count)
1405 : : return -ENOMEM;
1406 : :
1407 : : /* Obtain the address to map to. we verify (or select) it and ensure
1408 : : * that it represents a valid section of the address space.
1409 : : */
1410 : 613640 : addr = get_unmapped_area(file, addr, len, pgoff, flags);
1411 [ + - ]: 613640 : if (IS_ERR_VALUE(addr))
1412 : : return addr;
1413 : :
1414 [ + + ]: 613640 : if (flags & MAP_FIXED_NOREPLACE) {
1415 : 53991 : struct vm_area_struct *vma = find_vma(mm, addr);
1416 : :
1417 [ + - + - ]: 53991 : if (vma && vma->vm_start < addr + len)
1418 : : return -EEXIST;
1419 : : }
1420 : :
1421 [ - + ]: 613640 : if (prot == PROT_EXEC) {
1422 : 0 : pkey = execute_only_pkey(mm);
1423 : 0 : if (pkey < 0)
1424 : : pkey = 0;
1425 : : }
1426 : :
1427 : : /* Do simple checking here so the lower-level routines won't have
1428 : : * to. we assume access permissions have been handled by the open
1429 : : * of the memory object, so we don't do any here.
1430 : : */
1431 [ - + ]: 613640 : vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
1432 : 613640 : mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1433 : :
1434 [ - + ]: 613640 : if (flags & MAP_LOCKED)
1435 [ # # ]: 0 : if (!can_do_mlock())
1436 : : return -EPERM;
1437 : :
1438 [ + - ]: 613640 : if (mlock_future_check(mm, vm_flags, len))
1439 : : return -EAGAIN;
1440 : :
1441 [ + + ]: 613640 : if (file) {
1442 [ - + ]: 543060 : struct inode *inode = file_inode(file);
1443 : 543060 : unsigned long flags_mask;
1444 : :
1445 [ - + ]: 543060 : if (!file_mmap_ok(file, inode, pgoff, len))
1446 : : return -EOVERFLOW;
1447 : :
1448 : 543060 : flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags;
1449 : :
1450 [ + - + - ]: 543060 : switch (flags & MAP_TYPE) {
1451 : 10710 : case MAP_SHARED:
1452 : : /*
1453 : : * Force use of MAP_SHARED_VALIDATE with non-legacy
1454 : : * flags. E.g. MAP_SYNC is dangerous to use with
1455 : : * MAP_SHARED as you don't know which consistency model
1456 : : * you will get. We silently ignore unsupported flags
1457 : : * with MAP_SHARED to preserve backward compatibility.
1458 : : */
1459 : 10710 : flags &= LEGACY_MAP_MASK;
1460 : : /* fall through */
1461 : 10710 : case MAP_SHARED_VALIDATE:
1462 [ + - ]: 10710 : if (flags & ~flags_mask)
1463 : : return -EOPNOTSUPP;
1464 [ + + ]: 10710 : if (prot & PROT_WRITE) {
1465 [ + - ]: 84 : if (!(file->f_mode & FMODE_WRITE))
1466 : : return -EACCES;
1467 [ + - ]: 84 : if (IS_SWAPFILE(file->f_mapping->host))
1468 : : return -ETXTBSY;
1469 : : }
1470 : :
1471 : : /*
1472 : : * Make sure we don't allow writing to an append-only
1473 : : * file..
1474 : : */
1475 [ - + - - ]: 10710 : if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1476 : : return -EACCES;
1477 : :
1478 : : /*
1479 : : * Make sure there are no mandatory locks on the file.
1480 : : */
1481 [ + - ]: 10710 : if (locks_verify_locked(file))
1482 : : return -EAGAIN;
1483 : :
1484 : 10710 : vm_flags |= VM_SHARED | VM_MAYSHARE;
1485 [ + + ]: 10710 : if (!(file->f_mode & FMODE_WRITE))
1486 : 10626 : vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1487 : :
1488 : : /* fall through */
1489 : : case MAP_PRIVATE:
1490 [ + - ]: 543060 : if (!(file->f_mode & FMODE_READ))
1491 : : return -EACCES;
1492 [ - + ]: 543060 : if (path_noexec(&file->f_path)) {
1493 [ # # ]: 0 : if (vm_flags & VM_EXEC)
1494 : : return -EPERM;
1495 : 0 : vm_flags &= ~VM_MAYEXEC;
1496 : : }
1497 : :
1498 [ + - ]: 543060 : if (!file->f_op->mmap)
1499 : : return -ENODEV;
1500 [ + - ]: 543060 : if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1501 : : return -EINVAL;
1502 : : break;
1503 : :
1504 : : default:
1505 : : return -EINVAL;
1506 : : }
1507 : : } else {
1508 [ - + - ]: 70580 : switch (flags & MAP_TYPE) {
1509 : 0 : case MAP_SHARED:
1510 [ # # ]: 0 : if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1511 : : return -EINVAL;
1512 : : /*
1513 : : * Ignore pgoff.
1514 : : */
1515 : 0 : pgoff = 0;
1516 : 0 : vm_flags |= VM_SHARED | VM_MAYSHARE;
1517 : 0 : break;
1518 : 70580 : case MAP_PRIVATE:
1519 : : /*
1520 : : * Set pgoff according to addr for anon_vma.
1521 : : */
1522 : 70580 : pgoff = addr >> PAGE_SHIFT;
1523 : 70580 : break;
1524 : : default:
1525 : : return -EINVAL;
1526 : : }
1527 : : }
1528 : :
1529 : : /*
1530 : : * Set 'VM_NORESERVE' if we should not account for the
1531 : : * memory use of this mapping.
1532 : : */
1533 [ + + ]: 613640 : if (flags & MAP_NORESERVE) {
1534 : : /* We honor MAP_NORESERVE if allowed to overcommit */
1535 [ + - ]: 84 : if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1536 : 84 : vm_flags |= VM_NORESERVE;
1537 : :
1538 : : /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1539 [ - + - - ]: 84 : if (file && is_file_hugepages(file))
1540 : 0 : vm_flags |= VM_NORESERVE;
1541 : : }
1542 : :
1543 : 613640 : addr = mmap_region(file, addr, len, vm_flags, pgoff, uf);
1544 [ + - ]: 613640 : if (!IS_ERR_VALUE(addr) &&
1545 [ + - ]: 613640 : ((vm_flags & VM_LOCKED) ||
1546 [ - + ]: 613640 : (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE))
1547 : 0 : *populate = len;
1548 : : return addr;
1549 : : }
1550 : :
1551 : 469748 : unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
1552 : : unsigned long prot, unsigned long flags,
1553 : : unsigned long fd, unsigned long pgoff)
1554 : : {
1555 : 469748 : struct file *file = NULL;
1556 : 469748 : unsigned long retval;
1557 : :
1558 [ + + ]: 469748 : if (!(flags & MAP_ANONYMOUS)) {
1559 : 399168 : audit_mmap_fd(fd, flags);
1560 : 399168 : file = fget(fd);
1561 [ + - ]: 399168 : if (!file)
1562 : : return -EBADF;
1563 [ + - - + ]: 798336 : if (is_file_hugepages(file))
1564 : 0 : len = ALIGN(len, huge_page_size(hstate_file(file)));
1565 : 399168 : retval = -EINVAL;
1566 [ - + - - ]: 399168 : if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
1567 : 0 : goto out_fput;
1568 [ - + ]: 70580 : } else if (flags & MAP_HUGETLB) {
1569 : 0 : struct user_struct *user = NULL;
1570 : 0 : struct hstate *hs;
1571 : :
1572 [ # # ]: 0 : hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
1573 [ # # ]: 0 : if (!hs)
1574 : 0 : return -EINVAL;
1575 : :
1576 : 0 : len = ALIGN(len, huge_page_size(hs));
1577 : : /*
1578 : : * VM_NORESERVE is used because the reservations will be
1579 : : * taken when vm_ops->mmap() is called
1580 : : * A dummy user value is used because we are not locking
1581 : : * memory so no accounting is necessary
1582 : : */
1583 : 0 : file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
1584 : : VM_NORESERVE,
1585 : : &user, HUGETLB_ANONHUGE_INODE,
1586 : : (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
1587 [ # # ]: 0 : if (IS_ERR(file))
1588 : : return PTR_ERR(file);
1589 : : }
1590 : :
1591 : 469748 : flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1592 : :
1593 : 469748 : retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1594 : 469748 : out_fput:
1595 [ + + ]: 469748 : if (file)
1596 : 399168 : fput(file);
1597 : : return retval;
1598 : : }
1599 : :
1600 : 0 : SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1601 : : unsigned long, prot, unsigned long, flags,
1602 : : unsigned long, fd, unsigned long, pgoff)
1603 : : {
1604 : 0 : return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
1605 : : }
1606 : :
1607 : : #ifdef __ARCH_WANT_SYS_OLD_MMAP
1608 : : struct mmap_arg_struct {
1609 : : unsigned long addr;
1610 : : unsigned long len;
1611 : : unsigned long prot;
1612 : : unsigned long flags;
1613 : : unsigned long fd;
1614 : : unsigned long offset;
1615 : : };
1616 : :
1617 : : SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1618 : : {
1619 : : struct mmap_arg_struct a;
1620 : :
1621 : : if (copy_from_user(&a, arg, sizeof(a)))
1622 : : return -EFAULT;
1623 : : if (offset_in_page(a.offset))
1624 : : return -EINVAL;
1625 : :
1626 : : return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1627 : : a.offset >> PAGE_SHIFT);
1628 : : }
1629 : : #endif /* __ARCH_WANT_SYS_OLD_MMAP */
1630 : :
1631 : : /*
1632 : : * Some shared mappings will want the pages marked read-only
1633 : : * to track write events. If so, we'll downgrade vm_page_prot
1634 : : * to the private version (using protection_map[] without the
1635 : : * VM_SHARED bit).
1636 : : */
1637 : 878776 : int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot)
1638 : : {
1639 : 878776 : vm_flags_t vm_flags = vma->vm_flags;
1640 : 878776 : const struct vm_operations_struct *vm_ops = vma->vm_ops;
1641 : :
1642 : : /* If it was private or non-writable, the write bit is already clear */
1643 [ + + ]: 878776 : if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1644 : : return 0;
1645 : :
1646 : : /* The backer wishes to know when pages are first written to? */
1647 [ + - + - : 84 : if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite))
+ - ]
1648 : : return 1;
1649 : :
1650 : : /* The open routine did something to the protections that pgprot_modify
1651 : : * won't preserve? */
1652 [ + - + - ]: 168 : if (pgprot_val(vm_page_prot) !=
1653 : : pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags)))
1654 : : return 0;
1655 : :
1656 : : /* Do we need to track softdirty? */
1657 : 84 : if (IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) && !(vm_flags & VM_SOFTDIRTY))
1658 : : return 1;
1659 : :
1660 : : /* Specialty mapping? */
1661 [ + - ]: 84 : if (vm_flags & VM_PFNMAP)
1662 : : return 0;
1663 : :
1664 : : /* Can the mapping track the dirty pages? */
1665 [ + - + - : 168 : return vma->vm_file && vma->vm_file->f_mapping &&
+ - ]
1666 : 84 : mapping_cap_account_dirty(vma->vm_file->f_mapping);
1667 : : }
1668 : :
1669 : : /*
1670 : : * We account for memory if it's a private writeable mapping,
1671 : : * not hugepages and VM_NORESERVE wasn't set.
1672 : : */
1673 : 613640 : static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
1674 : : {
1675 : : /*
1676 : : * hugetlb has its own accounting separate from the core VM
1677 : : * VM_HUGETLB may not be set yet so we cannot check for that flag.
1678 : : */
1679 [ + + - + ]: 1156700 : if (file && is_file_hugepages(file))
1680 : 0 : return 0;
1681 : :
1682 : 613640 : return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1683 : : }
1684 : :
1685 : 613640 : unsigned long mmap_region(struct file *file, unsigned long addr,
1686 : : unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
1687 : : struct list_head *uf)
1688 : : {
1689 : 613640 : struct mm_struct *mm = current->mm;
1690 : 613640 : struct vm_area_struct *vma, *prev;
1691 : 613640 : int error;
1692 : 613640 : struct rb_node **rb_link, *rb_parent;
1693 : 613640 : unsigned long charged = 0;
1694 : :
1695 : : /* Check against address space limit. */
1696 [ - + ]: 613640 : if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
1697 : 0 : unsigned long nr_pages;
1698 : :
1699 : : /*
1700 : : * MAP_FIXED may remove pages of mappings that intersects with
1701 : : * requested mapping. Account for the pages it would unmap.
1702 : : */
1703 : 0 : nr_pages = count_vma_pages_range(mm, addr, addr + len);
1704 : :
1705 [ # # ]: 0 : if (!may_expand_vm(mm, vm_flags,
1706 : : (len >> PAGE_SHIFT) - nr_pages))
1707 : : return -ENOMEM;
1708 : : }
1709 : :
1710 : : /* Clear old maps */
1711 [ + + ]: 1648330 : while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
1712 : : &rb_parent)) {
1713 [ + - ]: 210525 : if (do_munmap(mm, addr, len, uf))
1714 : : return -ENOMEM;
1715 : : }
1716 : :
1717 : : /*
1718 : : * Private writable mapping: check memory availability
1719 : : */
1720 [ + + ]: 613640 : if (accountable_mapping(file, vm_flags)) {
1721 : 169700 : charged = len >> PAGE_SHIFT;
1722 [ + - ]: 169700 : if (security_vm_enough_memory_mm(mm, charged))
1723 : : return -ENOMEM;
1724 : 169700 : vm_flags |= VM_ACCOUNT;
1725 : : }
1726 : :
1727 : : /*
1728 : : * Can we just expand an old mapping?
1729 : : */
1730 : 613640 : vma = vma_merge(mm, prev, addr, addr + len, vm_flags,
1731 : : NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX);
1732 [ + + ]: 613640 : if (vma)
1733 : 50244 : goto out;
1734 : :
1735 : : /*
1736 : : * Determine the object being mapped and call the appropriate
1737 : : * specific mapper. the address has already been validated, but
1738 : : * not unmapped, but the maps are removed from the list.
1739 : : */
1740 : 563396 : vma = vm_area_alloc(mm);
1741 [ - + ]: 563396 : if (!vma) {
1742 : 0 : error = -ENOMEM;
1743 : 0 : goto unacct_error;
1744 : : }
1745 : :
1746 : 563396 : vma->vm_start = addr;
1747 : 563396 : vma->vm_end = addr + len;
1748 : 563396 : vma->vm_flags = vm_flags;
1749 [ + + ]: 563396 : vma->vm_page_prot = vm_get_page_prot(vm_flags);
1750 : 563396 : vma->vm_pgoff = pgoff;
1751 : :
1752 [ + + ]: 563396 : if (file) {
1753 [ + + ]: 511623 : if (vm_flags & VM_DENYWRITE) {
1754 : 143892 : error = deny_write_access(file);
1755 : 0 : if (error)
1756 : 0 : goto free_vma;
1757 : : }
1758 [ + + ]: 511623 : if (vm_flags & VM_SHARED) {
1759 : 84 : error = mapping_map_writable(file->f_mapping);
1760 : 0 : if (error)
1761 : 0 : goto allow_write_and_free_vma;
1762 : : }
1763 : :
1764 : : /* ->mmap() can change vma->vm_file, but must guarantee that
1765 : : * vma_link() below can deny write-access if VM_DENYWRITE is set
1766 : : * and map writably if VM_SHARED is set. This usually means the
1767 : : * new file must not have been exposed to user-space, yet.
1768 : : */
1769 : 511623 : vma->vm_file = get_file(file);
1770 : 511623 : error = call_mmap(file, vma);
1771 [ - + ]: 511623 : if (error)
1772 : 0 : goto unmap_and_free_vma;
1773 : :
1774 : : /* Can addr have changed??
1775 : : *
1776 : : * Answer: Yes, several device drivers can do it in their
1777 : : * f_op->mmap method. -DaveM
1778 : : * Bug: If addr is changed, prev, rb_link, rb_parent should
1779 : : * be updated for vma_link()
1780 : : */
1781 [ - + ]: 511623 : WARN_ON_ONCE(addr != vma->vm_start);
1782 : :
1783 : 511623 : addr = vma->vm_start;
1784 : 511623 : vm_flags = vma->vm_flags;
1785 [ - + ]: 51773 : } else if (vm_flags & VM_SHARED) {
1786 : 0 : error = shmem_zero_setup(vma);
1787 [ # # ]: 0 : if (error)
1788 : 0 : goto free_vma;
1789 : : } else {
1790 : 51773 : vma_set_anonymous(vma);
1791 : : }
1792 : :
1793 : 563396 : vma_link(mm, vma, prev, rb_link, rb_parent);
1794 : : /* Once vma denies write, undo our temporary denial count */
1795 [ + + ]: 563396 : if (file) {
1796 [ + + ]: 511623 : if (vm_flags & VM_SHARED)
1797 : 84 : mapping_unmap_writable(file->f_mapping);
1798 [ + + ]: 511623 : if (vm_flags & VM_DENYWRITE)
1799 : 143892 : allow_write_access(file);
1800 : : }
1801 : 563396 : file = vma->vm_file;
1802 : 613640 : out:
1803 : 613640 : perf_event_mmap(vma);
1804 : :
1805 : 613640 : vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT);
1806 [ - + ]: 613640 : if (vm_flags & VM_LOCKED) {
1807 [ # # # # ]: 0 : if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) ||
1808 [ # # # # ]: 0 : is_vm_hugetlb_page(vma) ||
1809 : 0 : vma == get_gate_vma(current->mm))
1810 : 0 : vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
1811 : : else
1812 : 0 : mm->locked_vm += (len >> PAGE_SHIFT);
1813 : : }
1814 : :
1815 [ + + ]: 613640 : if (file)
1816 : 543060 : uprobe_mmap(vma);
1817 : :
1818 : : /*
1819 : : * New (or expanded) vma always get soft dirty status.
1820 : : * Otherwise user-space soft-dirty page tracker won't
1821 : : * be able to distinguish situation when vma area unmapped,
1822 : : * then new mapped in-place (which must be aimed as
1823 : : * a completely new data area).
1824 : : */
1825 : 613640 : vma->vm_flags |= VM_SOFTDIRTY;
1826 : :
1827 : 613640 : vma_set_page_prot(vma);
1828 : :
1829 : 613640 : return addr;
1830 : :
1831 : : unmap_and_free_vma:
1832 : 0 : vma->vm_file = NULL;
1833 : 0 : fput(file);
1834 : :
1835 : : /* Undo any partial mapping done by a device driver. */
1836 : 0 : unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1837 : 0 : charged = 0;
1838 [ # # ]: 0 : if (vm_flags & VM_SHARED)
1839 : 0 : mapping_unmap_writable(file->f_mapping);
1840 : 0 : allow_write_and_free_vma:
1841 [ # # ]: 0 : if (vm_flags & VM_DENYWRITE)
1842 : 0 : allow_write_access(file);
1843 : 0 : free_vma:
1844 : 0 : vm_area_free(vma);
1845 : 0 : unacct_error:
1846 [ # # ]: 0 : if (charged)
1847 : 0 : vm_unacct_memory(charged);
1848 : 0 : return error;
1849 : : }
1850 : :
1851 : 0 : unsigned long unmapped_area(struct vm_unmapped_area_info *info)
1852 : : {
1853 : : /*
1854 : : * We implement the search by looking for an rbtree node that
1855 : : * immediately follows a suitable gap. That is,
1856 : : * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
1857 : : * - gap_end = vma->vm_start >= info->low_limit + length;
1858 : : * - gap_end - gap_start >= length
1859 : : */
1860 : :
1861 [ # # ]: 0 : struct mm_struct *mm = current->mm;
1862 : 0 : struct vm_area_struct *vma;
1863 : 0 : unsigned long length, low_limit, high_limit, gap_start, gap_end;
1864 : :
1865 : : /* Adjust search length to account for worst case alignment overhead */
1866 : 0 : length = info->length + info->align_mask;
1867 [ # # ]: 0 : if (length < info->length)
1868 : : return -ENOMEM;
1869 : :
1870 : : /* Adjust search limits by the desired length */
1871 [ # # ]: 0 : if (info->high_limit < length)
1872 : : return -ENOMEM;
1873 : 0 : high_limit = info->high_limit - length;
1874 : :
1875 [ # # ]: 0 : if (info->low_limit > high_limit)
1876 : : return -ENOMEM;
1877 : 0 : low_limit = info->low_limit + length;
1878 : :
1879 : : /* Check if rbtree root looks promising */
1880 [ # # ]: 0 : if (RB_EMPTY_ROOT(&mm->mm_rb))
1881 : 0 : goto check_highest;
1882 : 0 : vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1883 [ # # ]: 0 : if (vma->rb_subtree_gap < length)
1884 : 0 : goto check_highest;
1885 : :
1886 : 0 : while (true) {
1887 : : /* Visit left subtree if it looks promising */
1888 [ # # ]: 0 : gap_end = vm_start_gap(vma);
1889 [ # # # # ]: 0 : if (gap_end >= low_limit && vma->vm_rb.rb_left) {
1890 : 0 : struct vm_area_struct *left =
1891 : 0 : rb_entry(vma->vm_rb.rb_left,
1892 : : struct vm_area_struct, vm_rb);
1893 [ # # ]: 0 : if (left->rb_subtree_gap >= length) {
1894 : 0 : vma = left;
1895 : 0 : continue;
1896 : : }
1897 : : }
1898 : :
1899 [ # # ]: 0 : gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
1900 : 0 : check_current:
1901 : : /* Check if current node has a suitable gap */
1902 [ # # ]: 0 : if (gap_start > high_limit)
1903 : : return -ENOMEM;
1904 : 0 : if (gap_end >= low_limit &&
1905 [ # # # # ]: 0 : gap_end > gap_start && gap_end - gap_start >= length)
1906 : 0 : goto found;
1907 : :
1908 : : /* Visit right subtree if it looks promising */
1909 [ # # ]: 0 : if (vma->vm_rb.rb_right) {
1910 : 0 : struct vm_area_struct *right =
1911 : 0 : rb_entry(vma->vm_rb.rb_right,
1912 : : struct vm_area_struct, vm_rb);
1913 [ # # ]: 0 : if (right->rb_subtree_gap >= length) {
1914 : 0 : vma = right;
1915 : 0 : continue;
1916 : : }
1917 : : }
1918 : :
1919 : : /* Go back up the rbtree to find next candidate node */
1920 : 0 : while (true) {
1921 : 0 : struct rb_node *prev = &vma->vm_rb;
1922 [ # # ]: 0 : if (!rb_parent(prev))
1923 : 0 : goto check_highest;
1924 : 0 : vma = rb_entry(rb_parent(prev),
1925 : : struct vm_area_struct, vm_rb);
1926 [ # # ]: 0 : if (prev == vma->vm_rb.rb_left) {
1927 [ # # ]: 0 : gap_start = vm_end_gap(vma->vm_prev);
1928 [ # # ]: 0 : gap_end = vm_start_gap(vma);
1929 : 0 : goto check_current;
1930 : : }
1931 : : }
1932 : : }
1933 : :
1934 : 0 : check_highest:
1935 : : /* Check highest gap, which does not precede any rbtree node */
1936 : 0 : gap_start = mm->highest_vm_end;
1937 : 0 : gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */
1938 [ # # ]: 0 : if (gap_start > high_limit)
1939 : : return -ENOMEM;
1940 : :
1941 : 0 : found:
1942 : : /* We found a suitable gap. Clip it with the original low_limit. */
1943 : 0 : if (gap_start < info->low_limit)
1944 : : gap_start = info->low_limit;
1945 : :
1946 : : /* Adjust gap address to the desired alignment */
1947 : 0 : gap_start += (info->align_offset - gap_start) & info->align_mask;
1948 : :
1949 : 0 : VM_BUG_ON(gap_start + info->length > info->high_limit);
1950 : 0 : VM_BUG_ON(gap_start + info->length > gap_end);
1951 : 0 : return gap_start;
1952 : : }
1953 : :
1954 : 277203 : unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
1955 : : {
1956 [ + - ]: 277203 : struct mm_struct *mm = current->mm;
1957 : 277203 : struct vm_area_struct *vma;
1958 : 277203 : unsigned long length, low_limit, high_limit, gap_start, gap_end;
1959 : :
1960 : : /* Adjust search length to account for worst case alignment overhead */
1961 : 277203 : length = info->length + info->align_mask;
1962 [ + - ]: 277203 : if (length < info->length)
1963 : : return -ENOMEM;
1964 : :
1965 : : /*
1966 : : * Adjust search limits by the desired length.
1967 : : * See implementation comment at top of unmapped_area().
1968 : : */
1969 : 277203 : gap_end = info->high_limit;
1970 [ + - ]: 277203 : if (gap_end < length)
1971 : : return -ENOMEM;
1972 : 277203 : high_limit = gap_end - length;
1973 : :
1974 [ + - ]: 277203 : if (info->low_limit > high_limit)
1975 : : return -ENOMEM;
1976 : 277203 : low_limit = info->low_limit + length;
1977 : :
1978 : : /* Check highest gap, which does not precede any rbtree node */
1979 : 277203 : gap_start = mm->highest_vm_end;
1980 [ - + ]: 277203 : if (gap_start <= high_limit)
1981 : 0 : goto found_highest;
1982 : :
1983 : : /* Check if rbtree root looks promising */
1984 [ + - ]: 277203 : if (RB_EMPTY_ROOT(&mm->mm_rb))
1985 : : return -ENOMEM;
1986 : 277203 : vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1987 [ + - ]: 277203 : if (vma->rb_subtree_gap < length)
1988 : : return -ENOMEM;
1989 : :
1990 : 2165109 : while (true) {
1991 : : /* Visit right subtree if it looks promising */
1992 [ + - ]: 2165109 : gap_start = vma->vm_prev ? vm_end_gap(vma->vm_prev) : 0;
1993 [ + + + + ]: 2165109 : if (gap_start <= high_limit && vma->vm_rb.rb_right) {
1994 : 1538511 : struct vm_area_struct *right =
1995 : 1538511 : rb_entry(vma->vm_rb.rb_right,
1996 : : struct vm_area_struct, vm_rb);
1997 [ + + ]: 1538511 : if (right->rb_subtree_gap >= length) {
1998 : 974166 : vma = right;
1999 : 974166 : continue;
2000 : : }
2001 : : }
2002 : :
2003 : 1190943 : check_current:
2004 : : /* Check if current node has a suitable gap */
2005 [ + + ]: 1694310 : gap_end = vm_start_gap(vma);
2006 [ + - ]: 1694310 : if (gap_end < low_limit)
2007 : : return -ENOMEM;
2008 : 1694310 : if (gap_start <= high_limit &&
2009 [ + + + + ]: 1694310 : gap_end > gap_start && gap_end - gap_start >= length)
2010 : 277203 : goto found;
2011 : :
2012 : : /* Visit left subtree if it looks promising */
2013 [ + + ]: 1417107 : if (vma->vm_rb.rb_left) {
2014 : 1414377 : struct vm_area_struct *left =
2015 : 1414377 : rb_entry(vma->vm_rb.rb_left,
2016 : : struct vm_area_struct, vm_rb);
2017 [ + + ]: 1414377 : if (left->rb_subtree_gap >= length) {
2018 : 913740 : vma = left;
2019 : 913740 : continue;
2020 : : }
2021 : : }
2022 : :
2023 : : /* Go back up the rbtree to find next candidate node */
2024 : 506097 : while (true) {
2025 : 506097 : struct rb_node *prev = &vma->vm_rb;
2026 [ + - ]: 506097 : if (!rb_parent(prev))
2027 : : return -ENOMEM;
2028 : 506097 : vma = rb_entry(rb_parent(prev),
2029 : : struct vm_area_struct, vm_rb);
2030 [ + + ]: 506097 : if (prev == vma->vm_rb.rb_right) {
2031 : 503367 : gap_start = vma->vm_prev ?
2032 [ + - ]: 503367 : vm_end_gap(vma->vm_prev) : 0;
2033 : 503367 : goto check_current;
2034 : : }
2035 : : }
2036 : : }
2037 : :
2038 : : found:
2039 : : /* We found a suitable gap. Clip it with the original high_limit. */
2040 : 277203 : if (gap_end > info->high_limit)
2041 : : gap_end = info->high_limit;
2042 : :
2043 : 277203 : found_highest:
2044 : : /* Compute highest gap address at the desired alignment */
2045 : 277203 : gap_end -= info->length;
2046 : 277203 : gap_end -= (gap_end - info->align_offset) & info->align_mask;
2047 : :
2048 : 277203 : VM_BUG_ON(gap_end < info->low_limit);
2049 : 277203 : VM_BUG_ON(gap_end < gap_start);
2050 : 277203 : return gap_end;
2051 : : }
2052 : :
2053 : :
2054 : : #ifndef arch_get_mmap_end
2055 : : #define arch_get_mmap_end(addr) (TASK_SIZE)
2056 : : #endif
2057 : :
2058 : : #ifndef arch_get_mmap_base
2059 : : #define arch_get_mmap_base(addr, base) (base)
2060 : : #endif
2061 : :
2062 : : /* Get an address range which is currently unmapped.
2063 : : * For shmat() with addr=0.
2064 : : *
2065 : : * Ugly calling convention alert:
2066 : : * Return value with the low bits set means error value,
2067 : : * ie
2068 : : * if (ret & ~PAGE_MASK)
2069 : : * error = ret;
2070 : : *
2071 : : * This function "knows" that -ENOMEM has the bits set.
2072 : : */
2073 : : #ifndef HAVE_ARCH_UNMAPPED_AREA
2074 : : unsigned long
2075 : : arch_get_unmapped_area(struct file *filp, unsigned long addr,
2076 : : unsigned long len, unsigned long pgoff, unsigned long flags)
2077 : : {
2078 : : struct mm_struct *mm = current->mm;
2079 : : struct vm_area_struct *vma, *prev;
2080 : : struct vm_unmapped_area_info info;
2081 : : const unsigned long mmap_end = arch_get_mmap_end(addr);
2082 : :
2083 : : if (len > mmap_end - mmap_min_addr)
2084 : : return -ENOMEM;
2085 : :
2086 : : if (flags & MAP_FIXED)
2087 : : return addr;
2088 : :
2089 : : if (addr) {
2090 : : addr = PAGE_ALIGN(addr);
2091 : : vma = find_vma_prev(mm, addr, &prev);
2092 : : if (mmap_end - len >= addr && addr >= mmap_min_addr &&
2093 : : (!vma || addr + len <= vm_start_gap(vma)) &&
2094 : : (!prev || addr >= vm_end_gap(prev)))
2095 : : return addr;
2096 : : }
2097 : :
2098 : : info.flags = 0;
2099 : : info.length = len;
2100 : : info.low_limit = mm->mmap_base;
2101 : : info.high_limit = mmap_end;
2102 : : info.align_mask = 0;
2103 : : return vm_unmapped_area(&info);
2104 : : }
2105 : : #endif
2106 : :
2107 : : /*
2108 : : * This mmap-allocator allocates new areas top-down from below the
2109 : : * stack's low limit (the base):
2110 : : */
2111 : : #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
2112 : : unsigned long
2113 : : arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
2114 : : unsigned long len, unsigned long pgoff,
2115 : : unsigned long flags)
2116 : : {
2117 : : struct vm_area_struct *vma, *prev;
2118 : : struct mm_struct *mm = current->mm;
2119 : : struct vm_unmapped_area_info info;
2120 : : const unsigned long mmap_end = arch_get_mmap_end(addr);
2121 : :
2122 : : /* requested length too big for entire address space */
2123 : : if (len > mmap_end - mmap_min_addr)
2124 : : return -ENOMEM;
2125 : :
2126 : : if (flags & MAP_FIXED)
2127 : : return addr;
2128 : :
2129 : : /* requesting a specific address */
2130 : : if (addr) {
2131 : : addr = PAGE_ALIGN(addr);
2132 : : vma = find_vma_prev(mm, addr, &prev);
2133 : : if (mmap_end - len >= addr && addr >= mmap_min_addr &&
2134 : : (!vma || addr + len <= vm_start_gap(vma)) &&
2135 : : (!prev || addr >= vm_end_gap(prev)))
2136 : : return addr;
2137 : : }
2138 : :
2139 : : info.flags = VM_UNMAPPED_AREA_TOPDOWN;
2140 : : info.length = len;
2141 : : info.low_limit = max(PAGE_SIZE, mmap_min_addr);
2142 : : info.high_limit = arch_get_mmap_base(addr, mm->mmap_base);
2143 : : info.align_mask = 0;
2144 : : addr = vm_unmapped_area(&info);
2145 : :
2146 : : /*
2147 : : * A failed mmap() very likely causes application failure,
2148 : : * so fall back to the bottom-up function here. This scenario
2149 : : * can happen with large stack limits and large mmap()
2150 : : * allocations.
2151 : : */
2152 : : if (offset_in_page(addr)) {
2153 : : VM_BUG_ON(addr != -ENOMEM);
2154 : : info.flags = 0;
2155 : : info.low_limit = TASK_UNMAPPED_BASE;
2156 : : info.high_limit = mmap_end;
2157 : : addr = vm_unmapped_area(&info);
2158 : : }
2159 : :
2160 : : return addr;
2161 : : }
2162 : : #endif
2163 : :
2164 : : unsigned long
2165 : 673911 : get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
2166 : : unsigned long pgoff, unsigned long flags)
2167 : : {
2168 : 673911 : unsigned long (*get_area)(struct file *, unsigned long,
2169 : : unsigned long, unsigned long, unsigned long);
2170 : :
2171 : 673911 : unsigned long error = arch_mmap_check(addr, len, flags);
2172 : 673911 : if (error)
2173 : : return error;
2174 : :
2175 : : /* Careful about overflows.. */
2176 [ - + - - : 1347822 : if (len > TASK_SIZE)
+ - ]
2177 : : return -ENOMEM;
2178 : :
2179 [ + + ]: 673911 : get_area = current->mm->get_unmapped_area;
2180 [ + + ]: 673911 : if (file) {
2181 [ + + ]: 543060 : if (file->f_op->get_unmapped_area)
2182 : 63 : get_area = file->f_op->get_unmapped_area;
2183 [ - + ]: 130851 : } else if (flags & MAP_SHARED) {
2184 : : /*
2185 : : * mmap_region() will call shmem_zero_setup() to create a file,
2186 : : * so use shmem's get_unmapped_area in case it can be huge.
2187 : : * do_mmap_pgoff() will clear pgoff, so match alignment.
2188 : : */
2189 : 0 : pgoff = 0;
2190 : 0 : get_area = shmem_get_unmapped_area;
2191 : : }
2192 : :
2193 : 673911 : addr = get_area(file, addr, len, pgoff, flags);
2194 [ + - ]: 673911 : if (IS_ERR_VALUE(addr))
2195 : : return addr;
2196 : :
2197 [ - + - - : 1347822 : if (addr > TASK_SIZE - len)
+ - ]
2198 : : return -ENOMEM;
2199 [ + - ]: 673911 : if (offset_in_page(addr))
2200 : : return -EINVAL;
2201 : :
2202 : 673911 : error = security_mmap_addr(addr);
2203 [ + - ]: 673911 : return error ? error : addr;
2204 : : }
2205 : :
2206 : : EXPORT_SYMBOL(get_unmapped_area);
2207 : :
2208 : : /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
2209 : 3187989 : struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
2210 : : {
2211 : 3187989 : struct rb_node *rb_node;
2212 : 3187989 : struct vm_area_struct *vma;
2213 : :
2214 : : /* Check the cache first. */
2215 : 3187989 : vma = vmacache_find(mm, addr);
2216 [ + + ]: 3187989 : if (likely(vma))
2217 : : return vma;
2218 : :
2219 : 2093457 : rb_node = mm->mm_rb.rb_node;
2220 : :
2221 [ + + ]: 10904170 : while (rb_node) {
2222 : 10757310 : struct vm_area_struct *tmp;
2223 : :
2224 : 10757310 : tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
2225 : :
2226 [ + + ]: 10757310 : if (tmp->vm_end > addr) {
2227 : 6820189 : vma = tmp;
2228 [ + + ]: 6820189 : if (tmp->vm_start <= addr)
2229 : : break;
2230 : 4873592 : rb_node = rb_node->rb_left;
2231 : : } else
2232 : 3937121 : rb_node = rb_node->rb_right;
2233 : : }
2234 : :
2235 [ + + ]: 2093457 : if (vma)
2236 : 2075460 : vmacache_update(addr, vma);
2237 : : return vma;
2238 : : }
2239 : :
2240 : : EXPORT_SYMBOL(find_vma);
2241 : :
2242 : : /*
2243 : : * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
2244 : : */
2245 : : struct vm_area_struct *
2246 : 0 : find_vma_prev(struct mm_struct *mm, unsigned long addr,
2247 : : struct vm_area_struct **pprev)
2248 : : {
2249 : 0 : struct vm_area_struct *vma;
2250 : :
2251 : 0 : vma = find_vma(mm, addr);
2252 [ # # ]: 0 : if (vma) {
2253 : 0 : *pprev = vma->vm_prev;
2254 : : } else {
2255 : 0 : struct rb_node *rb_node = rb_last(&mm->mm_rb);
2256 : :
2257 [ # # ]: 0 : *pprev = rb_node ? rb_entry(rb_node, struct vm_area_struct, vm_rb) : NULL;
2258 : : }
2259 : 0 : return vma;
2260 : : }
2261 : :
2262 : : /*
2263 : : * Verify that the stack growth is acceptable and
2264 : : * update accounting. This is shared with both the
2265 : : * grow-up and grow-down cases.
2266 : : */
2267 : : static int acct_stack_growth(struct vm_area_struct *vma,
2268 : : unsigned long size, unsigned long grow)
2269 : : {
2270 : : struct mm_struct *mm = vma->vm_mm;
2271 : : unsigned long new_start;
2272 : :
2273 : : /* address space limit tests */
2274 : : if (!may_expand_vm(mm, vma->vm_flags, grow))
2275 : : return -ENOMEM;
2276 : :
2277 : : /* Stack limit test */
2278 : : if (size > rlimit(RLIMIT_STACK))
2279 : : return -ENOMEM;
2280 : :
2281 : : /* mlock limit tests */
2282 : : if (vma->vm_flags & VM_LOCKED) {
2283 : : unsigned long locked;
2284 : : unsigned long limit;
2285 : : locked = mm->locked_vm + grow;
2286 : : limit = rlimit(RLIMIT_MEMLOCK);
2287 : : limit >>= PAGE_SHIFT;
2288 : : if (locked > limit && !capable(CAP_IPC_LOCK))
2289 : : return -ENOMEM;
2290 : : }
2291 : :
2292 : : /* Check to ensure the stack will not grow into a hugetlb-only region */
2293 : : new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
2294 : : vma->vm_end - size;
2295 : : if (is_hugepage_only_range(vma->vm_mm, new_start, size))
2296 : : return -EFAULT;
2297 : :
2298 : : /*
2299 : : * Overcommit.. This must be the final test, as it will
2300 : : * update security statistics.
2301 : : */
2302 : : if (security_vm_enough_memory_mm(mm, grow))
2303 : : return -ENOMEM;
2304 : :
2305 : : return 0;
2306 : : }
2307 : :
2308 : : #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
2309 : : /*
2310 : : * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
2311 : : * vma is the last one with address > vma->vm_end. Have to extend vma.
2312 : : */
2313 : : int expand_upwards(struct vm_area_struct *vma, unsigned long address)
2314 : : {
2315 : : struct mm_struct *mm = vma->vm_mm;
2316 : : struct vm_area_struct *next;
2317 : : unsigned long gap_addr;
2318 : : int error = 0;
2319 : :
2320 : : if (!(vma->vm_flags & VM_GROWSUP))
2321 : : return -EFAULT;
2322 : :
2323 : : /* Guard against exceeding limits of the address space. */
2324 : : address &= PAGE_MASK;
2325 : : if (address >= (TASK_SIZE & PAGE_MASK))
2326 : : return -ENOMEM;
2327 : : address += PAGE_SIZE;
2328 : :
2329 : : /* Enforce stack_guard_gap */
2330 : : gap_addr = address + stack_guard_gap;
2331 : :
2332 : : /* Guard against overflow */
2333 : : if (gap_addr < address || gap_addr > TASK_SIZE)
2334 : : gap_addr = TASK_SIZE;
2335 : :
2336 : : next = vma->vm_next;
2337 : : if (next && next->vm_start < gap_addr &&
2338 : : (next->vm_flags & (VM_WRITE|VM_READ|VM_EXEC))) {
2339 : : if (!(next->vm_flags & VM_GROWSUP))
2340 : : return -ENOMEM;
2341 : : /* Check that both stack segments have the same anon_vma? */
2342 : : }
2343 : :
2344 : : /* We must make sure the anon_vma is allocated. */
2345 : : if (unlikely(anon_vma_prepare(vma)))
2346 : : return -ENOMEM;
2347 : :
2348 : : /*
2349 : : * vma->vm_start/vm_end cannot change under us because the caller
2350 : : * is required to hold the mmap_sem in read mode. We need the
2351 : : * anon_vma lock to serialize against concurrent expand_stacks.
2352 : : */
2353 : : anon_vma_lock_write(vma->anon_vma);
2354 : :
2355 : : /* Somebody else might have raced and expanded it already */
2356 : : if (address > vma->vm_end) {
2357 : : unsigned long size, grow;
2358 : :
2359 : : size = address - vma->vm_start;
2360 : : grow = (address - vma->vm_end) >> PAGE_SHIFT;
2361 : :
2362 : : error = -ENOMEM;
2363 : : if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
2364 : : error = acct_stack_growth(vma, size, grow);
2365 : : if (!error) {
2366 : : /*
2367 : : * vma_gap_update() doesn't support concurrent
2368 : : * updates, but we only hold a shared mmap_sem
2369 : : * lock here, so we need to protect against
2370 : : * concurrent vma expansions.
2371 : : * anon_vma_lock_write() doesn't help here, as
2372 : : * we don't guarantee that all growable vmas
2373 : : * in a mm share the same root anon vma.
2374 : : * So, we reuse mm->page_table_lock to guard
2375 : : * against concurrent vma expansions.
2376 : : */
2377 : : spin_lock(&mm->page_table_lock);
2378 : : if (vma->vm_flags & VM_LOCKED)
2379 : : mm->locked_vm += grow;
2380 : : vm_stat_account(mm, vma->vm_flags, grow);
2381 : : anon_vma_interval_tree_pre_update_vma(vma);
2382 : : vma->vm_end = address;
2383 : : anon_vma_interval_tree_post_update_vma(vma);
2384 : : if (vma->vm_next)
2385 : : vma_gap_update(vma->vm_next);
2386 : : else
2387 : : mm->highest_vm_end = vm_end_gap(vma);
2388 : : spin_unlock(&mm->page_table_lock);
2389 : :
2390 : : perf_event_mmap(vma);
2391 : : }
2392 : : }
2393 : : }
2394 : : anon_vma_unlock_write(vma->anon_vma);
2395 : : khugepaged_enter_vma_merge(vma, vma->vm_flags);
2396 : : validate_mm(mm);
2397 : : return error;
2398 : : }
2399 : : #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
2400 : :
2401 : : /*
2402 : : * vma is the first one with address < vma->vm_start. Have to extend vma.
2403 : : */
2404 : 17997 : int expand_downwards(struct vm_area_struct *vma,
2405 : : unsigned long address)
2406 : : {
2407 : 17997 : struct mm_struct *mm = vma->vm_mm;
2408 : 17997 : struct vm_area_struct *prev;
2409 : 17997 : int error = 0;
2410 : :
2411 : 17997 : address &= PAGE_MASK;
2412 [ + - ]: 17997 : if (address < mmap_min_addr)
2413 : : return -EPERM;
2414 : :
2415 : : /* Enforce stack_guard_gap */
2416 : 17997 : prev = vma->vm_prev;
2417 : : /* Check that both stack segments have the same anon_vma? */
2418 [ - + - - ]: 17997 : if (prev && !(prev->vm_flags & VM_GROWSDOWN) &&
2419 [ # # ]: 0 : (prev->vm_flags & (VM_WRITE|VM_READ|VM_EXEC))) {
2420 [ # # ]: 0 : if (address - prev->vm_end < stack_guard_gap)
2421 : : return -ENOMEM;
2422 : : }
2423 : :
2424 : : /* We must make sure the anon_vma is allocated. */
2425 [ - + + - ]: 17997 : if (unlikely(anon_vma_prepare(vma)))
2426 : : return -ENOMEM;
2427 : :
2428 : : /*
2429 : : * vma->vm_start/vm_end cannot change under us because the caller
2430 : : * is required to hold the mmap_sem in read mode. We need the
2431 : : * anon_vma lock to serialize against concurrent expand_stacks.
2432 : : */
2433 : 17997 : anon_vma_lock_write(vma->anon_vma);
2434 : :
2435 : : /* Somebody else might have raced and expanded it already */
2436 [ + - ]: 17997 : if (address < vma->vm_start) {
2437 : 17997 : unsigned long size, grow;
2438 : :
2439 : 17997 : size = vma->vm_end - address;
2440 : 17997 : grow = (vma->vm_start - address) >> PAGE_SHIFT;
2441 : :
2442 : 17997 : error = -ENOMEM;
2443 [ + - ]: 17997 : if (grow <= vma->vm_pgoff) {
2444 : 17997 : error = acct_stack_growth(vma, size, grow);
2445 [ + - ]: 17997 : if (!error) {
2446 : : /*
2447 : : * vma_gap_update() doesn't support concurrent
2448 : : * updates, but we only hold a shared mmap_sem
2449 : : * lock here, so we need to protect against
2450 : : * concurrent vma expansions.
2451 : : * anon_vma_lock_write() doesn't help here, as
2452 : : * we don't guarantee that all growable vmas
2453 : : * in a mm share the same root anon vma.
2454 : : * So, we reuse mm->page_table_lock to guard
2455 : : * against concurrent vma expansions.
2456 : : */
2457 : 17997 : spin_lock(&mm->page_table_lock);
2458 [ - + ]: 17997 : if (vma->vm_flags & VM_LOCKED)
2459 : 0 : mm->locked_vm += grow;
2460 : 17997 : vm_stat_account(mm, vma->vm_flags, grow);
2461 : 17997 : anon_vma_interval_tree_pre_update_vma(vma);
2462 : 17997 : vma->vm_start = address;
2463 : 17997 : vma->vm_pgoff -= grow;
2464 : 17997 : anon_vma_interval_tree_post_update_vma(vma);
2465 : 17997 : vma_gap_update(vma);
2466 : 17997 : spin_unlock(&mm->page_table_lock);
2467 : :
2468 : 17997 : perf_event_mmap(vma);
2469 : : }
2470 : : }
2471 : : }
2472 : 17997 : anon_vma_unlock_write(vma->anon_vma);
2473 : 17997 : khugepaged_enter_vma_merge(vma, vma->vm_flags);
2474 : 17997 : validate_mm(mm);
2475 : 17997 : return error;
2476 : : }
2477 : :
2478 : : /* enforced gap between the expanding stack and other mappings. */
2479 : : unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
2480 : :
2481 : 0 : static int __init cmdline_parse_stack_guard_gap(char *p)
2482 : : {
2483 : 0 : unsigned long val;
2484 : 0 : char *endptr;
2485 : :
2486 : 0 : val = simple_strtoul(p, &endptr, 10);
2487 [ # # ]: 0 : if (!*endptr)
2488 : 0 : stack_guard_gap = val << PAGE_SHIFT;
2489 : :
2490 : 0 : return 0;
2491 : : }
2492 : : __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
2493 : :
2494 : : #ifdef CONFIG_STACK_GROWSUP
2495 : : int expand_stack(struct vm_area_struct *vma, unsigned long address)
2496 : : {
2497 : : return expand_upwards(vma, address);
2498 : : }
2499 : :
2500 : : struct vm_area_struct *
2501 : : find_extend_vma(struct mm_struct *mm, unsigned long addr)
2502 : : {
2503 : : struct vm_area_struct *vma, *prev;
2504 : :
2505 : : addr &= PAGE_MASK;
2506 : : vma = find_vma_prev(mm, addr, &prev);
2507 : : if (vma && (vma->vm_start <= addr))
2508 : : return vma;
2509 : : /* don't alter vm_end if the coredump is running */
2510 : : if (!prev || !mmget_still_valid(mm) || expand_stack(prev, addr))
2511 : : return NULL;
2512 : : if (prev->vm_flags & VM_LOCKED)
2513 : : populate_vma_page_range(prev, addr, prev->vm_end, NULL);
2514 : : return prev;
2515 : : }
2516 : : #else
2517 : 17997 : int expand_stack(struct vm_area_struct *vma, unsigned long address)
2518 : : {
2519 : 17997 : return expand_downwards(vma, address);
2520 : : }
2521 : :
2522 : : struct vm_area_struct *
2523 : 74211 : find_extend_vma(struct mm_struct *mm, unsigned long addr)
2524 : : {
2525 : 74211 : struct vm_area_struct *vma;
2526 : 74211 : unsigned long start;
2527 : :
2528 : 74211 : addr &= PAGE_MASK;
2529 : 74211 : vma = find_vma(mm, addr);
2530 [ + - ]: 74211 : if (!vma)
2531 : : return NULL;
2532 [ - + ]: 74211 : if (vma->vm_start <= addr)
2533 : : return vma;
2534 [ # # ]: 0 : if (!(vma->vm_flags & VM_GROWSDOWN))
2535 : : return NULL;
2536 : : /* don't alter vm_start if the coredump is running */
2537 [ # # ]: 0 : if (!mmget_still_valid(mm))
2538 : : return NULL;
2539 : 0 : start = vma->vm_start;
2540 [ # # ]: 0 : if (expand_stack(vma, addr))
2541 : : return NULL;
2542 [ # # ]: 0 : if (vma->vm_flags & VM_LOCKED)
2543 : 0 : populate_vma_page_range(vma, addr, start, NULL);
2544 : : return vma;
2545 : : }
2546 : : #endif
2547 : :
2548 : : EXPORT_SYMBOL_GPL(find_extend_vma);
2549 : :
2550 : : /*
2551 : : * Ok - we have the memory areas we should free on the vma list,
2552 : : * so release them, and do the vma updates.
2553 : : *
2554 : : * Called with the mm semaphore held.
2555 : : */
2556 : 274450 : static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
2557 : : {
2558 : 274450 : unsigned long nr_accounted = 0;
2559 : :
2560 : : /* Update high watermark before we lower total_vm */
2561 [ + + ]: 274450 : update_hiwater_vm(mm);
2562 : 274534 : do {
2563 [ + + ]: 274534 : long nrpages = vma_pages(vma);
2564 : :
2565 [ + + ]: 274534 : if (vma->vm_flags & VM_ACCOUNT)
2566 : 6146 : nr_accounted += nrpages;
2567 : 274534 : vm_stat_account(mm, vma->vm_flags, -nrpages);
2568 : 274534 : vma = remove_vma(vma);
2569 [ + + ]: 274534 : } while (vma);
2570 : 274450 : vm_unacct_memory(nr_accounted);
2571 : 274450 : validate_mm(mm);
2572 : 274450 : }
2573 : :
2574 : : /*
2575 : : * Get rid of page table information in the indicated region.
2576 : : *
2577 : : * Called with the mm semaphore held.
2578 : : */
2579 : 274450 : static void unmap_region(struct mm_struct *mm,
2580 : : struct vm_area_struct *vma, struct vm_area_struct *prev,
2581 : : unsigned long start, unsigned long end)
2582 : : {
2583 [ + - ]: 274450 : struct vm_area_struct *next = prev ? prev->vm_next : mm->mmap;
2584 : 274450 : struct mmu_gather tlb;
2585 : :
2586 : 274450 : lru_add_drain();
2587 : 274450 : tlb_gather_mmu(&tlb, mm, start, end);
2588 : 274450 : update_hiwater_rss(mm);
2589 : 274450 : unmap_vmas(&tlb, vma, start, end);
2590 [ + - + - ]: 274450 : free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
2591 : : next ? next->vm_start : USER_PGTABLES_CEILING);
2592 : 274450 : tlb_finish_mmu(&tlb, start, end);
2593 : 274450 : }
2594 : :
2595 : : /*
2596 : : * Create a list of vma's touched by the unmap, removing them from the mm's
2597 : : * vma list as we go..
2598 : : */
2599 : : static void
2600 : 274450 : detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
2601 : : struct vm_area_struct *prev, unsigned long end)
2602 : : {
2603 : 274450 : struct vm_area_struct **insertion_point;
2604 : 274450 : struct vm_area_struct *tail_vma = NULL;
2605 : :
2606 [ + - ]: 274450 : insertion_point = (prev ? &prev->vm_next : &mm->mmap);
2607 : 274450 : vma->vm_prev = NULL;
2608 : 274534 : do {
2609 : 274534 : vma_rb_erase(vma, &mm->mm_rb);
2610 : 274534 : mm->map_count--;
2611 : 274534 : tail_vma = vma;
2612 : 274534 : vma = vma->vm_next;
2613 [ + - + + ]: 274534 : } while (vma && vma->vm_start < end);
2614 : 274450 : *insertion_point = vma;
2615 [ + - ]: 274450 : if (vma) {
2616 : 274450 : vma->vm_prev = prev;
2617 : 274450 : vma_gap_update(vma);
2618 : : } else
2619 [ # # ]: 0 : mm->highest_vm_end = prev ? vm_end_gap(prev) : 0;
2620 : 274450 : tail_vma->vm_next = NULL;
2621 : :
2622 : : /* Kill the cache */
2623 : 274450 : vmacache_invalidate(mm);
2624 : 274450 : }
2625 : :
2626 : : /*
2627 : : * __split_vma() bypasses sysctl_max_map_count checking. We use this where it
2628 : : * has already been checked or doesn't make sense to fail.
2629 : : */
2630 : 410584 : int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2631 : : unsigned long addr, int new_below)
2632 : : {
2633 : 410584 : struct vm_area_struct *new;
2634 : 410584 : int err;
2635 : :
2636 [ + + - + ]: 410584 : if (vma->vm_ops && vma->vm_ops->split) {
2637 : 0 : err = vma->vm_ops->split(vma, addr);
2638 [ # # ]: 0 : if (err)
2639 : : return err;
2640 : : }
2641 : :
2642 : 410584 : new = vm_area_dup(vma);
2643 [ + - ]: 410584 : if (!new)
2644 : : return -ENOMEM;
2645 : :
2646 [ + + ]: 410584 : if (new_below)
2647 : 179465 : new->vm_end = addr;
2648 : : else {
2649 : 231119 : new->vm_start = addr;
2650 : 231119 : new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
2651 : : }
2652 : :
2653 : 410584 : err = vma_dup_policy(vma, new);
2654 [ - + ]: 410584 : if (err)
2655 : 0 : goto out_free_vma;
2656 : :
2657 : 410584 : err = anon_vma_clone(new, vma);
2658 [ - + ]: 410584 : if (err)
2659 : 0 : goto out_free_mpol;
2660 : :
2661 [ + + ]: 410584 : if (new->vm_file)
2662 : 409101 : get_file(new->vm_file);
2663 : :
2664 [ + + - + ]: 410584 : if (new->vm_ops && new->vm_ops->open)
2665 : 0 : new->vm_ops->open(new);
2666 : :
2667 [ + + ]: 410584 : if (new_below)
2668 : 179465 : err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
2669 : 179465 : ((addr - new->vm_start) >> PAGE_SHIFT), new);
2670 : : else
2671 : 231119 : err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
2672 : :
2673 : : /* Success. */
2674 [ - + ]: 410584 : if (!err)
2675 : : return 0;
2676 : :
2677 : : /* Clean everything up if vma_adjust failed. */
2678 [ # # # # ]: 0 : if (new->vm_ops && new->vm_ops->close)
2679 : 0 : new->vm_ops->close(new);
2680 [ # # ]: 0 : if (new->vm_file)
2681 : 0 : fput(new->vm_file);
2682 : 0 : unlink_anon_vmas(new);
2683 : 0 : out_free_mpol:
2684 [ # # ]: 0 : mpol_put(vma_policy(new));
2685 : 0 : out_free_vma:
2686 : 0 : vm_area_free(new);
2687 : 0 : return err;
2688 : : }
2689 : :
2690 : : /*
2691 : : * Split a vma into two pieces at address 'addr', a new vma is allocated
2692 : : * either for the first part or the tail.
2693 : : */
2694 : 163183 : int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2695 : : unsigned long addr, int new_below)
2696 : : {
2697 [ + - ]: 163183 : if (mm->map_count >= sysctl_max_map_count)
2698 : : return -ENOMEM;
2699 : :
2700 : 163183 : return __split_vma(mm, vma, addr, new_below);
2701 : : }
2702 : :
2703 : : /* Munmap is split into 2 main parts -- this part which finds
2704 : : * what needs doing, and the areas themselves, which do the
2705 : : * work. This now handles partial unmappings.
2706 : : * Jeremy Fitzhardinge <jeremy@goop.org>
2707 : : */
2708 : 274450 : int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
2709 : : struct list_head *uf, bool downgrade)
2710 : : {
2711 : 274450 : unsigned long end;
2712 : 274450 : struct vm_area_struct *vma, *prev, *last;
2713 : :
2714 [ + - - + : 1372250 : if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
- - + - -
+ - - -
+ ]
2715 : 0 : return -EINVAL;
2716 : :
2717 : 274450 : len = PAGE_ALIGN(len);
2718 : 274450 : end = start + len;
2719 [ + - ]: 274450 : if (len == 0)
2720 : : return -EINVAL;
2721 : :
2722 : : /*
2723 : : * arch_unmap() might do unmaps itself. It must be called
2724 : : * and finish any rbtree manipulation before this code
2725 : : * runs and also starts to manipulate the rbtree.
2726 : : */
2727 : 274450 : arch_unmap(mm, start, end);
2728 : :
2729 : : /* Find the first overlapping VMA */
2730 : 274450 : vma = find_vma(mm, start);
2731 [ + - ]: 274450 : if (!vma)
2732 : : return 0;
2733 : 274450 : prev = vma->vm_prev;
2734 : : /* we have start < vma->vm_end */
2735 : :
2736 : : /* if it doesn't overlap, we have nothing.. */
2737 [ + - ]: 274450 : if (vma->vm_start >= end)
2738 : : return 0;
2739 : :
2740 : : /*
2741 : : * If we need to split any vma, do it now to save pain later.
2742 : : *
2743 : : * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2744 : : * unmapped vm_area_struct will remain in use: so lower split_vma
2745 : : * places tmp vma above, and higher split_vma places tmp vma below.
2746 : : */
2747 [ + + ]: 274450 : if (start > vma->vm_start) {
2748 : 99852 : int error;
2749 : :
2750 : : /*
2751 : : * Make sure that map_count on return from munmap() will
2752 : : * not exceed its limit; but let map_count go just above
2753 : : * its limit temporarily, to help free resources as expected.
2754 : : */
2755 [ + + + - ]: 99852 : if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2756 : : return -ENOMEM;
2757 : :
2758 : 99852 : error = __split_vma(mm, vma, start, 0);
2759 [ + - ]: 99852 : if (error)
2760 : : return error;
2761 : : prev = vma;
2762 : : }
2763 : :
2764 : : /* Does it split the last one? */
2765 : 274450 : last = find_vma(mm, end);
2766 [ + - + + ]: 274450 : if (last && end > last->vm_start) {
2767 : 147549 : int error = __split_vma(mm, last, end, 1);
2768 [ + - ]: 147549 : if (error)
2769 : : return error;
2770 : : }
2771 [ + - ]: 274450 : vma = prev ? prev->vm_next : mm->mmap;
2772 : :
2773 : 274450 : if (unlikely(uf)) {
2774 : : /*
2775 : : * If userfaultfd_unmap_prep returns an error the vmas
2776 : : * will remain splitted, but userland will get a
2777 : : * highly unexpected error anyway. This is no
2778 : : * different than the case where the first of the two
2779 : : * __split_vma fails, but we don't undo the first
2780 : : * split, despite we could. This is unlikely enough
2781 : : * failure that it's not worth optimizing it for.
2782 : : */
2783 : : int error = userfaultfd_unmap_prep(vma, start, end, uf);
2784 : : if (error)
2785 : : return error;
2786 : : }
2787 : :
2788 : : /*
2789 : : * unlock any mlock()ed ranges before detaching vmas
2790 : : */
2791 [ - + ]: 274450 : if (mm->locked_vm) {
2792 : : struct vm_area_struct *tmp = vma;
2793 [ # # # # ]: 0 : while (tmp && tmp->vm_start < end) {
2794 [ # # ]: 0 : if (tmp->vm_flags & VM_LOCKED) {
2795 : 0 : mm->locked_vm -= vma_pages(tmp);
2796 : 0 : munlock_vma_pages_all(tmp);
2797 : : }
2798 : :
2799 : 0 : tmp = tmp->vm_next;
2800 : : }
2801 : : }
2802 : :
2803 : : /* Detach vmas from rbtree */
2804 : 274450 : detach_vmas_to_be_unmapped(mm, vma, prev, end);
2805 : :
2806 [ + + ]: 274450 : if (downgrade)
2807 : 27931 : downgrade_write(&mm->mmap_sem);
2808 : :
2809 : 274450 : unmap_region(mm, vma, prev, start, end);
2810 : :
2811 : : /* Fix up all other VM information */
2812 : 274450 : remove_vma_list(mm, vma);
2813 : :
2814 : 274450 : return downgrade ? 1 : 0;
2815 : : }
2816 : :
2817 : 210525 : int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
2818 : : struct list_head *uf)
2819 : : {
2820 : 210525 : return __do_munmap(mm, start, len, uf, false);
2821 : : }
2822 : :
2823 : 63197 : static int __vm_munmap(unsigned long start, size_t len, bool downgrade)
2824 : : {
2825 : 63197 : int ret;
2826 : 63197 : struct mm_struct *mm = current->mm;
2827 : 63197 : LIST_HEAD(uf);
2828 : :
2829 [ + - ]: 63197 : if (down_write_killable(&mm->mmap_sem))
2830 : : return -EINTR;
2831 : :
2832 : 63197 : ret = __do_munmap(mm, start, len, &uf, downgrade);
2833 : : /*
2834 : : * Returning 1 indicates mmap_sem is downgraded.
2835 : : * But 1 is not legal return value of vm_munmap() and munmap(), reset
2836 : : * it to 0 before return.
2837 : : */
2838 [ + + ]: 63197 : if (ret == 1) {
2839 : 27203 : up_read(&mm->mmap_sem);
2840 : 27203 : ret = 0;
2841 : : } else
2842 : 35994 : up_write(&mm->mmap_sem);
2843 : :
2844 : : userfaultfd_unmap_complete(mm, &uf);
2845 : : return ret;
2846 : : }
2847 : :
2848 : 35994 : int vm_munmap(unsigned long start, size_t len)
2849 : : {
2850 : 35994 : return __vm_munmap(start, len, false);
2851 : : }
2852 : : EXPORT_SYMBOL(vm_munmap);
2853 : :
2854 : 54406 : SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
2855 : : {
2856 : 27203 : addr = untagged_addr(addr);
2857 : 27203 : profile_munmap(addr);
2858 : 27203 : return __vm_munmap(addr, len, true);
2859 : : }
2860 : :
2861 : :
2862 : : /*
2863 : : * Emulation of deprecated remap_file_pages() syscall.
2864 : : */
2865 : 0 : SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
2866 : : unsigned long, prot, unsigned long, pgoff, unsigned long, flags)
2867 : : {
2868 : :
2869 [ # # ]: 0 : struct mm_struct *mm = current->mm;
2870 : 0 : struct vm_area_struct *vma;
2871 : 0 : unsigned long populate = 0;
2872 : 0 : unsigned long ret = -EINVAL;
2873 : 0 : struct file *file;
2874 : :
2875 [ # # ]: 0 : pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.rst.\n",
2876 : : current->comm, current->pid);
2877 : :
2878 [ # # ]: 0 : if (prot)
2879 : : return ret;
2880 : 0 : start = start & PAGE_MASK;
2881 : 0 : size = size & PAGE_MASK;
2882 : :
2883 [ # # ]: 0 : if (start + size <= start)
2884 : : return ret;
2885 : :
2886 : : /* Does pgoff wrap? */
2887 [ # # ]: 0 : if (pgoff + (size >> PAGE_SHIFT) < pgoff)
2888 : : return ret;
2889 : :
2890 [ # # ]: 0 : if (down_write_killable(&mm->mmap_sem))
2891 : : return -EINTR;
2892 : :
2893 : 0 : vma = find_vma(mm, start);
2894 : :
2895 [ # # # # ]: 0 : if (!vma || !(vma->vm_flags & VM_SHARED))
2896 : 0 : goto out;
2897 : :
2898 [ # # ]: 0 : if (start < vma->vm_start)
2899 : 0 : goto out;
2900 : :
2901 [ # # ]: 0 : if (start + size > vma->vm_end) {
2902 : 0 : struct vm_area_struct *next;
2903 : :
2904 [ # # ]: 0 : for (next = vma->vm_next; next; next = next->vm_next) {
2905 : : /* hole between vmas ? */
2906 [ # # ]: 0 : if (next->vm_start != next->vm_prev->vm_end)
2907 : 0 : goto out;
2908 : :
2909 [ # # ]: 0 : if (next->vm_file != vma->vm_file)
2910 : 0 : goto out;
2911 : :
2912 [ # # ]: 0 : if (next->vm_flags != vma->vm_flags)
2913 : 0 : goto out;
2914 : :
2915 [ # # ]: 0 : if (start + size <= next->vm_end)
2916 : : break;
2917 : : }
2918 : :
2919 [ # # ]: 0 : if (!next)
2920 : 0 : goto out;
2921 : : }
2922 : :
2923 : 0 : prot |= vma->vm_flags & VM_READ ? PROT_READ : 0;
2924 : 0 : prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0;
2925 : 0 : prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0;
2926 : :
2927 : 0 : flags &= MAP_NONBLOCK;
2928 : 0 : flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
2929 [ # # ]: 0 : if (vma->vm_flags & VM_LOCKED) {
2930 : 0 : struct vm_area_struct *tmp;
2931 : 0 : flags |= MAP_LOCKED;
2932 : :
2933 : : /* drop PG_Mlocked flag for over-mapped range */
2934 [ # # ]: 0 : for (tmp = vma; tmp->vm_start >= start + size;
2935 : 0 : tmp = tmp->vm_next) {
2936 : : /*
2937 : : * Split pmd and munlock page on the border
2938 : : * of the range.
2939 : : */
2940 : 0 : vma_adjust_trans_huge(tmp, start, start + size, 0);
2941 : :
2942 : 0 : munlock_vma_pages_range(tmp,
2943 : 0 : max(tmp->vm_start, start),
2944 : 0 : min(tmp->vm_end, start + size));
2945 : : }
2946 : : }
2947 : :
2948 : 0 : file = get_file(vma->vm_file);
2949 : 0 : ret = do_mmap_pgoff(vma->vm_file, start, size,
2950 : : prot, flags, pgoff, &populate, NULL);
2951 : 0 : fput(file);
2952 : 0 : out:
2953 : 0 : up_write(&mm->mmap_sem);
2954 [ # # ]: 0 : if (populate)
2955 : 0 : mm_populate(ret, populate);
2956 [ # # ]: 0 : if (!IS_ERR_VALUE(ret))
2957 : 0 : ret = 0;
2958 : 0 : return ret;
2959 : : }
2960 : :
2961 : : /*
2962 : : * this is really a simplified "do_mmap". it only handles
2963 : : * anonymous maps. eventually we may be able to do some
2964 : : * brk-specific accounting here.
2965 : : */
2966 : 42274 : static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long flags, struct list_head *uf)
2967 : : {
2968 [ + - ]: 42274 : struct mm_struct *mm = current->mm;
2969 : 42274 : struct vm_area_struct *vma, *prev;
2970 : 42274 : struct rb_node **rb_link, *rb_parent;
2971 : 42274 : pgoff_t pgoff = addr >> PAGE_SHIFT;
2972 : 42274 : int error;
2973 : 42274 : unsigned long mapped_addr;
2974 : :
2975 : : /* Until we need other flags, refuse anything except VM_EXEC. */
2976 [ + - ]: 42274 : if ((flags & (~VM_EXEC)) != 0)
2977 : : return -EINVAL;
2978 [ + - ]: 42274 : flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2979 : :
2980 : 42274 : mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2981 [ - + ]: 42274 : if (IS_ERR_VALUE(mapped_addr))
2982 : 0 : return mapped_addr;
2983 : :
2984 : 42274 : error = mlock_future_check(mm, mm->def_flags, len);
2985 [ + - ]: 42274 : if (error)
2986 : : return error;
2987 : :
2988 : : /*
2989 : : * Clear old maps. this also does some error checking for us
2990 : : */
2991 [ - + ]: 84548 : while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
2992 : : &rb_parent)) {
2993 [ # # ]: 0 : if (do_munmap(mm, addr, len, uf))
2994 : : return -ENOMEM;
2995 : : }
2996 : :
2997 : : /* Check against address space limits *after* clearing old maps... */
2998 [ + - ]: 42274 : if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))
2999 : : return -ENOMEM;
3000 : :
3001 [ + - ]: 42274 : if (mm->map_count > sysctl_max_map_count)
3002 : : return -ENOMEM;
3003 : :
3004 [ + - ]: 42274 : if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
3005 : : return -ENOMEM;
3006 : :
3007 : : /* Can we just expand an old private anonymous mapping? */
3008 : 42274 : vma = vma_merge(mm, prev, addr, addr + len, flags,
3009 : : NULL, NULL, pgoff, NULL, NULL_VM_UFFD_CTX);
3010 [ + + ]: 42274 : if (vma)
3011 : 402 : goto out;
3012 : :
3013 : : /*
3014 : : * create a vma struct for an anonymous mapping
3015 : : */
3016 : 41872 : vma = vm_area_alloc(mm);
3017 [ - + ]: 41872 : if (!vma) {
3018 : 0 : vm_unacct_memory(len >> PAGE_SHIFT);
3019 : 0 : return -ENOMEM;
3020 : : }
3021 : :
3022 [ + - ]: 41872 : vma_set_anonymous(vma);
3023 : 41872 : vma->vm_start = addr;
3024 : 41872 : vma->vm_end = addr + len;
3025 : 41872 : vma->vm_pgoff = pgoff;
3026 : 41872 : vma->vm_flags = flags;
3027 [ + - ]: 41872 : vma->vm_page_prot = vm_get_page_prot(flags);
3028 : 41872 : vma_link(mm, vma, prev, rb_link, rb_parent);
3029 : 42274 : out:
3030 : 42274 : perf_event_mmap(vma);
3031 : 42274 : mm->total_vm += len >> PAGE_SHIFT;
3032 : 42274 : mm->data_vm += len >> PAGE_SHIFT;
3033 [ - + ]: 42274 : if (flags & VM_LOCKED)
3034 : 0 : mm->locked_vm += (len >> PAGE_SHIFT);
3035 : 42274 : vma->vm_flags |= VM_SOFTDIRTY;
3036 : 42274 : return 0;
3037 : : }
3038 : :
3039 : 23877 : int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
3040 : : {
3041 [ + - ]: 23877 : struct mm_struct *mm = current->mm;
3042 : 23877 : unsigned long len;
3043 : 23877 : int ret;
3044 : 23877 : bool populate;
3045 : 23877 : LIST_HEAD(uf);
3046 : :
3047 : 23877 : len = PAGE_ALIGN(request);
3048 [ + - ]: 23877 : if (len < request)
3049 : : return -ENOMEM;
3050 [ + - ]: 23877 : if (!len)
3051 : : return 0;
3052 : :
3053 [ + - ]: 23877 : if (down_write_killable(&mm->mmap_sem))
3054 : : return -EINTR;
3055 : :
3056 : 23877 : ret = do_brk_flags(addr, len, flags, &uf);
3057 : 23877 : populate = ((mm->def_flags & VM_LOCKED) != 0);
3058 : 23877 : up_write(&mm->mmap_sem);
3059 [ - + ]: 23877 : userfaultfd_unmap_complete(mm, &uf);
3060 [ - + ]: 23877 : if (populate && !ret)
3061 : 0 : mm_populate(addr, len);
3062 : : return ret;
3063 : : }
3064 : : EXPORT_SYMBOL(vm_brk_flags);
3065 : :
3066 : 0 : int vm_brk(unsigned long addr, unsigned long len)
3067 : : {
3068 : 0 : return vm_brk_flags(addr, len, 0);
3069 : : }
3070 : : EXPORT_SYMBOL(vm_brk);
3071 : :
3072 : : /* Release all mmaps. */
3073 : 35007 : void exit_mmap(struct mm_struct *mm)
3074 : : {
3075 : 35007 : struct mmu_gather tlb;
3076 : 35007 : struct vm_area_struct *vma;
3077 : 35007 : unsigned long nr_accounted = 0;
3078 : :
3079 : : /* mm's last user has gone, and its about to be pulled down */
3080 [ - + ]: 35007 : mmu_notifier_release(mm);
3081 : :
3082 [ - + ]: 35007 : if (unlikely(mm_is_oom_victim(mm))) {
3083 : : /*
3084 : : * Manually reap the mm to free as much memory as possible.
3085 : : * Then, as the oom reaper does, set MMF_OOM_SKIP to disregard
3086 : : * this mm from further consideration. Taking mm->mmap_sem for
3087 : : * write after setting MMF_OOM_SKIP will guarantee that the oom
3088 : : * reaper will not run on this mm again after mmap_sem is
3089 : : * dropped.
3090 : : *
3091 : : * Nothing can be holding mm->mmap_sem here and the above call
3092 : : * to mmu_notifier_release(mm) ensures mmu notifier callbacks in
3093 : : * __oom_reap_task_mm() will not block.
3094 : : *
3095 : : * This needs to be done before calling munlock_vma_pages_all(),
3096 : : * which clears VM_LOCKED, otherwise the oom reaper cannot
3097 : : * reliably test it.
3098 : : */
3099 : 0 : (void)__oom_reap_task_mm(mm);
3100 : :
3101 : 0 : set_bit(MMF_OOM_SKIP, &mm->flags);
3102 : 0 : down_write(&mm->mmap_sem);
3103 : 0 : up_write(&mm->mmap_sem);
3104 : : }
3105 : :
3106 [ - + ]: 35007 : if (mm->locked_vm) {
3107 : 0 : vma = mm->mmap;
3108 [ # # ]: 0 : while (vma) {
3109 [ # # ]: 0 : if (vma->vm_flags & VM_LOCKED)
3110 : 0 : munlock_vma_pages_all(vma);
3111 : 0 : vma = vma->vm_next;
3112 : : }
3113 : : }
3114 : :
3115 : 35007 : arch_exit_mmap(mm);
3116 : :
3117 : 35007 : vma = mm->mmap;
3118 [ - + ]: 35007 : if (!vma) /* Can happen if dup_mmap() received an OOM */
3119 : 0 : return;
3120 : :
3121 : 35007 : lru_add_drain();
3122 : 35007 : flush_cache_mm(mm);
3123 : 35007 : tlb_gather_mmu(&tlb, mm, 0, -1);
3124 : : /* update_hiwater_rss(mm) here? but nobody should be looking */
3125 : : /* Use -1 here to ensure all VMAs in the mm are unmapped */
3126 : 35007 : unmap_vmas(&tlb, vma, 0, -1);
3127 : 35007 : free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING);
3128 : 35007 : tlb_finish_mmu(&tlb, 0, -1);
3129 : :
3130 : : /*
3131 : : * Walk the list again, actually closing and freeing it,
3132 : : * with preemption enabled, without holding any MM locks.
3133 : : */
3134 [ + + ]: 1802113 : while (vma) {
3135 [ + + ]: 1767106 : if (vma->vm_flags & VM_ACCOUNT)
3136 : 702238 : nr_accounted += vma_pages(vma);
3137 : 1767106 : vma = remove_vma(vma);
3138 : : }
3139 : 35007 : vm_unacct_memory(nr_accounted);
3140 : : }
3141 : :
3142 : : /* Insert vm structure into process list sorted by address
3143 : : * and into the inode's i_mmap tree. If vm_file is non-NULL
3144 : : * then i_mmap_rwsem is taken here.
3145 : : */
3146 : 53991 : int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
3147 : : {
3148 : 53991 : struct vm_area_struct *prev;
3149 : 53991 : struct rb_node **rb_link, *rb_parent;
3150 : :
3151 [ + - ]: 107982 : if (find_vma_links(mm, vma->vm_start, vma->vm_end,
3152 : : &prev, &rb_link, &rb_parent))
3153 : : return -ENOMEM;
3154 [ + + + - ]: 71988 : if ((vma->vm_flags & VM_ACCOUNT) &&
3155 : 17997 : security_vm_enough_memory_mm(mm, vma_pages(vma)))
3156 : : return -ENOMEM;
3157 : :
3158 : : /*
3159 : : * The vm_pgoff of a purely anonymous vma should be irrelevant
3160 : : * until its first write fault, when page's anon_vma and index
3161 : : * are set. But now set the vm_pgoff it will almost certainly
3162 : : * end up with (unless mremap moves it elsewhere before that
3163 : : * first wfault), so /proc/pid/maps tells a consistent story.
3164 : : *
3165 : : * By setting it to reflect the virtual start address of the
3166 : : * vma, merges and splits can happen in a seamless way, just
3167 : : * using the existing file pgoff checks and manipulations.
3168 : : * Similarly in do_mmap_pgoff and in do_brk.
3169 : : */
3170 [ + + ]: 53991 : if (vma_is_anonymous(vma)) {
3171 [ - + ]: 17997 : BUG_ON(vma->anon_vma);
3172 : 17997 : vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
3173 : : }
3174 : :
3175 : 53991 : vma_link(mm, vma, prev, rb_link, rb_parent);
3176 : 53991 : return 0;
3177 : : }
3178 : :
3179 : : /*
3180 : : * Copy the vma structure to a new location in the same mm,
3181 : : * prior to moving page table entries, to effect an mremap move.
3182 : : */
3183 : 0 : struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
3184 : : unsigned long addr, unsigned long len, pgoff_t pgoff,
3185 : : bool *need_rmap_locks)
3186 : : {
3187 : 0 : struct vm_area_struct *vma = *vmap;
3188 : 0 : unsigned long vma_start = vma->vm_start;
3189 : 0 : struct mm_struct *mm = vma->vm_mm;
3190 : 0 : struct vm_area_struct *new_vma, *prev;
3191 : 0 : struct rb_node **rb_link, *rb_parent;
3192 : 0 : bool faulted_in_anon_vma = true;
3193 : :
3194 : : /*
3195 : : * If anonymous vma has not yet been faulted, update new pgoff
3196 : : * to match new location, to increase its chance of merging.
3197 : : */
3198 [ # # # # ]: 0 : if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) {
3199 : 0 : pgoff = addr >> PAGE_SHIFT;
3200 : 0 : faulted_in_anon_vma = false;
3201 : : }
3202 : :
3203 [ # # ]: 0 : if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
3204 : : return NULL; /* should never get here */
3205 : 0 : new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
3206 : : vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
3207 : : vma->vm_userfaultfd_ctx);
3208 [ # # ]: 0 : if (new_vma) {
3209 : : /*
3210 : : * Source vma may have been merged into new_vma
3211 : : */
3212 [ # # # # ]: 0 : if (unlikely(vma_start >= new_vma->vm_start &&
3213 : : vma_start < new_vma->vm_end)) {
3214 : : /*
3215 : : * The only way we can get a vma_merge with
3216 : : * self during an mremap is if the vma hasn't
3217 : : * been faulted in yet and we were allowed to
3218 : : * reset the dst vma->vm_pgoff to the
3219 : : * destination address of the mremap to allow
3220 : : * the merge to happen. mremap must change the
3221 : : * vm_pgoff linearity between src and dst vmas
3222 : : * (in turn preventing a vma_merge) to be
3223 : : * safe. It is only safe to keep the vm_pgoff
3224 : : * linear if there are no pages mapped yet.
3225 : : */
3226 : 0 : VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma);
3227 : 0 : *vmap = vma = new_vma;
3228 : : }
3229 : 0 : *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
3230 : : } else {
3231 : 0 : new_vma = vm_area_dup(vma);
3232 [ # # ]: 0 : if (!new_vma)
3233 : 0 : goto out;
3234 : 0 : new_vma->vm_start = addr;
3235 : 0 : new_vma->vm_end = addr + len;
3236 : 0 : new_vma->vm_pgoff = pgoff;
3237 [ # # ]: 0 : if (vma_dup_policy(vma, new_vma))
3238 : 0 : goto out_free_vma;
3239 [ # # ]: 0 : if (anon_vma_clone(new_vma, vma))
3240 : 0 : goto out_free_mempol;
3241 [ # # ]: 0 : if (new_vma->vm_file)
3242 : 0 : get_file(new_vma->vm_file);
3243 [ # # # # ]: 0 : if (new_vma->vm_ops && new_vma->vm_ops->open)
3244 : 0 : new_vma->vm_ops->open(new_vma);
3245 : 0 : vma_link(mm, new_vma, prev, rb_link, rb_parent);
3246 : 0 : *need_rmap_locks = false;
3247 : : }
3248 : : return new_vma;
3249 : :
3250 : : out_free_mempol:
3251 [ # # ]: 0 : mpol_put(vma_policy(new_vma));
3252 : 0 : out_free_vma:
3253 : 0 : vm_area_free(new_vma);
3254 : : out:
3255 : : return NULL;
3256 : : }
3257 : :
3258 : : /*
3259 : : * Return true if the calling process may expand its vm space by the passed
3260 : : * number of pages
3261 : : */
3262 : 675334 : bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
3263 : : {
3264 [ + - ]: 675334 : if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT)
3265 : : return false;
3266 : :
3267 [ + + - + ]: 675334 : if (is_data_mapping(flags) &&
3268 [ - + ]: 213397 : mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
3269 : : /* Workaround for Valgrind */
3270 [ # # ]: 0 : if (rlimit(RLIMIT_DATA) == 0 &&
3271 [ # # ]: 0 : mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
3272 : : return true;
3273 : :
3274 [ # # # # ]: 0 : pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
3275 : : current->comm, current->pid,
3276 : : (mm->data_vm + npages) << PAGE_SHIFT,
3277 : : rlimit(RLIMIT_DATA),
3278 : : ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data");
3279 : :
3280 [ # # ]: 0 : if (!ignore_rlimit_data)
3281 : 0 : return false;
3282 : : }
3283 : :
3284 : : return true;
3285 : : }
3286 : :
3287 : 1207301 : void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages)
3288 : : {
3289 : 1207301 : mm->total_vm += npages;
3290 : :
3291 [ + + + + : 1171307 : if (is_exec_mapping(flags))
- + + + ]
3292 : 137214 : mm->exec_vm += npages;
3293 [ - + - + : 1070087 : else if (is_stack_mapping(flags))
- + + - -
+ ]
3294 : 17997 : mm->stack_vm += npages;
3295 [ - + + + : 1052090 : else if (is_data_mapping(flags))
+ + - - +
+ ]
3296 : 276536 : mm->data_vm += npages;
3297 : 265136 : }
3298 : :
3299 : : static vm_fault_t special_mapping_fault(struct vm_fault *vmf);
3300 : :
3301 : : /*
3302 : : * Having a close hook prevents vma merging regardless of flags.
3303 : : */
3304 : 70014 : static void special_mapping_close(struct vm_area_struct *vma)
3305 : : {
3306 : 70014 : }
3307 : :
3308 : 0 : static const char *special_mapping_name(struct vm_area_struct *vma)
3309 : : {
3310 : 0 : return ((struct vm_special_mapping *)vma->vm_private_data)->name;
3311 : : }
3312 : :
3313 : 0 : static int special_mapping_mremap(struct vm_area_struct *new_vma)
3314 : : {
3315 : 0 : struct vm_special_mapping *sm = new_vma->vm_private_data;
3316 : :
3317 [ # # # # ]: 0 : if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
3318 : : return -EFAULT;
3319 : :
3320 [ # # ]: 0 : if (sm->mremap)
3321 : 0 : return sm->mremap(sm, new_vma);
3322 : :
3323 : : return 0;
3324 : : }
3325 : :
3326 : : static const struct vm_operations_struct special_mapping_vmops = {
3327 : : .close = special_mapping_close,
3328 : : .fault = special_mapping_fault,
3329 : : .mremap = special_mapping_mremap,
3330 : : .name = special_mapping_name,
3331 : : /* vDSO code relies that VVAR can't be accessed remotely */
3332 : : .access = NULL,
3333 : : };
3334 : :
3335 : : static const struct vm_operations_struct legacy_special_mapping_vmops = {
3336 : : .close = special_mapping_close,
3337 : : .fault = special_mapping_fault,
3338 : : };
3339 : :
3340 : 19732 : static vm_fault_t special_mapping_fault(struct vm_fault *vmf)
3341 : : {
3342 : 19732 : struct vm_area_struct *vma = vmf->vma;
3343 : 19732 : pgoff_t pgoff;
3344 : 19732 : struct page **pages;
3345 : :
3346 [ - + ]: 19732 : if (vma->vm_ops == &legacy_special_mapping_vmops) {
3347 : 0 : pages = vma->vm_private_data;
3348 : : } else {
3349 : 19732 : struct vm_special_mapping *sm = vma->vm_private_data;
3350 : :
3351 [ + - ]: 19732 : if (sm->fault)
3352 : 19732 : return sm->fault(sm, vmf->vma, vmf);
3353 : :
3354 : 0 : pages = sm->pages;
3355 : : }
3356 : :
3357 [ # # # # ]: 0 : for (pgoff = vmf->pgoff; pgoff && *pages; ++pages)
3358 : 0 : pgoff--;
3359 : :
3360 [ # # ]: 0 : if (*pages) {
3361 : 0 : struct page *page = *pages;
3362 [ # # ]: 0 : get_page(page);
3363 : 0 : vmf->page = page;
3364 : 0 : return 0;
3365 : : }
3366 : :
3367 : : return VM_FAULT_SIGBUS;
3368 : : }
3369 : :
3370 : 35994 : static struct vm_area_struct *__install_special_mapping(
3371 : : struct mm_struct *mm,
3372 : : unsigned long addr, unsigned long len,
3373 : : unsigned long vm_flags, void *priv,
3374 : : const struct vm_operations_struct *ops)
3375 : : {
3376 : 35994 : int ret;
3377 : 35994 : struct vm_area_struct *vma;
3378 : :
3379 : 35994 : vma = vm_area_alloc(mm);
3380 [ + - ]: 35994 : if (unlikely(vma == NULL))
3381 : : return ERR_PTR(-ENOMEM);
3382 : :
3383 : 35994 : vma->vm_start = addr;
3384 : 35994 : vma->vm_end = addr + len;
3385 : :
3386 : 35994 : vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY;
3387 [ + - ]: 35994 : vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
3388 : :
3389 : 35994 : vma->vm_ops = ops;
3390 : 35994 : vma->vm_private_data = priv;
3391 : :
3392 : 35994 : ret = insert_vm_struct(mm, vma);
3393 [ - + ]: 35994 : if (ret)
3394 : 0 : goto out;
3395 : :
3396 [ + + ]: 35994 : vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT);
3397 : :
3398 : 35994 : perf_event_mmap(vma);
3399 : :
3400 : 35994 : return vma;
3401 : :
3402 : : out:
3403 : 0 : vm_area_free(vma);
3404 : 0 : return ERR_PTR(ret);
3405 : : }
3406 : :
3407 : 0 : bool vma_is_special_mapping(const struct vm_area_struct *vma,
3408 : : const struct vm_special_mapping *sm)
3409 : : {
3410 [ # # ]: 0 : return vma->vm_private_data == sm &&
3411 [ # # # # ]: 0 : (vma->vm_ops == &special_mapping_vmops ||
3412 : : vma->vm_ops == &legacy_special_mapping_vmops);
3413 : : }
3414 : :
3415 : : /*
3416 : : * Called with mm->mmap_sem held for writing.
3417 : : * Insert a new vma covering the given region, with the given flags.
3418 : : * Its pages are supplied by the given array of struct page *.
3419 : : * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
3420 : : * The region past the last page supplied will always produce SIGBUS.
3421 : : * The array pointer and the pages it points to are assumed to stay alive
3422 : : * for as long as this mapping might exist.
3423 : : */
3424 : 35994 : struct vm_area_struct *_install_special_mapping(
3425 : : struct mm_struct *mm,
3426 : : unsigned long addr, unsigned long len,
3427 : : unsigned long vm_flags, const struct vm_special_mapping *spec)
3428 : : {
3429 : 35994 : return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec,
3430 : : &special_mapping_vmops);
3431 : : }
3432 : :
3433 : 0 : int install_special_mapping(struct mm_struct *mm,
3434 : : unsigned long addr, unsigned long len,
3435 : : unsigned long vm_flags, struct page **pages)
3436 : : {
3437 : 0 : struct vm_area_struct *vma = __install_special_mapping(
3438 : : mm, addr, len, vm_flags, (void *)pages,
3439 : : &legacy_special_mapping_vmops);
3440 : :
3441 [ # # ]: 0 : return PTR_ERR_OR_ZERO(vma);
3442 : : }
3443 : :
3444 : : static DEFINE_MUTEX(mm_all_locks_mutex);
3445 : :
3446 : : static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
3447 : : {
3448 : : if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) {
3449 : : /*
3450 : : * The LSB of head.next can't change from under us
3451 : : * because we hold the mm_all_locks_mutex.
3452 : : */
3453 : : down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
3454 : : /*
3455 : : * We can safely modify head.next after taking the
3456 : : * anon_vma->root->rwsem. If some other vma in this mm shares
3457 : : * the same anon_vma we won't take it again.
3458 : : *
3459 : : * No need of atomic instructions here, head.next
3460 : : * can't change from under us thanks to the
3461 : : * anon_vma->root->rwsem.
3462 : : */
3463 : : if (__test_and_set_bit(0, (unsigned long *)
3464 : : &anon_vma->root->rb_root.rb_root.rb_node))
3465 : : BUG();
3466 : : }
3467 : : }
3468 : :
3469 : : static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
3470 : : {
3471 : : if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3472 : : /*
3473 : : * AS_MM_ALL_LOCKS can't change from under us because
3474 : : * we hold the mm_all_locks_mutex.
3475 : : *
3476 : : * Operations on ->flags have to be atomic because
3477 : : * even if AS_MM_ALL_LOCKS is stable thanks to the
3478 : : * mm_all_locks_mutex, there may be other cpus
3479 : : * changing other bitflags in parallel to us.
3480 : : */
3481 : : if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
3482 : : BUG();
3483 : : down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_sem);
3484 : : }
3485 : : }
3486 : :
3487 : : /*
3488 : : * This operation locks against the VM for all pte/vma/mm related
3489 : : * operations that could ever happen on a certain mm. This includes
3490 : : * vmtruncate, try_to_unmap, and all page faults.
3491 : : *
3492 : : * The caller must take the mmap_sem in write mode before calling
3493 : : * mm_take_all_locks(). The caller isn't allowed to release the
3494 : : * mmap_sem until mm_drop_all_locks() returns.
3495 : : *
3496 : : * mmap_sem in write mode is required in order to block all operations
3497 : : * that could modify pagetables and free pages without need of
3498 : : * altering the vma layout. It's also needed in write mode to avoid new
3499 : : * anon_vmas to be associated with existing vmas.
3500 : : *
3501 : : * A single task can't take more than one mm_take_all_locks() in a row
3502 : : * or it would deadlock.
3503 : : *
3504 : : * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
3505 : : * mapping->flags avoid to take the same lock twice, if more than one
3506 : : * vma in this mm is backed by the same anon_vma or address_space.
3507 : : *
3508 : : * We take locks in following order, accordingly to comment at beginning
3509 : : * of mm/rmap.c:
3510 : : * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for
3511 : : * hugetlb mapping);
3512 : : * - all i_mmap_rwsem locks;
3513 : : * - all anon_vma->rwseml
3514 : : *
3515 : : * We can take all locks within these types randomly because the VM code
3516 : : * doesn't nest them and we protected from parallel mm_take_all_locks() by
3517 : : * mm_all_locks_mutex.
3518 : : *
3519 : : * mm_take_all_locks() and mm_drop_all_locks are expensive operations
3520 : : * that may have to take thousand of locks.
3521 : : *
3522 : : * mm_take_all_locks() can fail if it's interrupted by signals.
3523 : : */
3524 : 0 : int mm_take_all_locks(struct mm_struct *mm)
3525 : : {
3526 : 0 : struct vm_area_struct *vma;
3527 : 0 : struct anon_vma_chain *avc;
3528 : :
3529 [ # # ]: 0 : BUG_ON(down_read_trylock(&mm->mmap_sem));
3530 : :
3531 : 0 : mutex_lock(&mm_all_locks_mutex);
3532 : :
3533 [ # # ]: 0 : for (vma = mm->mmap; vma; vma = vma->vm_next) {
3534 [ # # ]: 0 : if (signal_pending(current))
3535 : 0 : goto out_unlock;
3536 [ # # # # : 0 : if (vma->vm_file && vma->vm_file->f_mapping &&
# # ]
3537 [ # # ]: 0 : is_vm_hugetlb_page(vma))
3538 : 0 : vm_lock_mapping(mm, vma->vm_file->f_mapping);
3539 : : }
3540 : :
3541 [ # # ]: 0 : for (vma = mm->mmap; vma; vma = vma->vm_next) {
3542 [ # # ]: 0 : if (signal_pending(current))
3543 : 0 : goto out_unlock;
3544 [ # # # # : 0 : if (vma->vm_file && vma->vm_file->f_mapping &&
# # ]
3545 [ # # ]: 0 : !is_vm_hugetlb_page(vma))
3546 : 0 : vm_lock_mapping(mm, vma->vm_file->f_mapping);
3547 : : }
3548 : :
3549 [ # # ]: 0 : for (vma = mm->mmap; vma; vma = vma->vm_next) {
3550 [ # # ]: 0 : if (signal_pending(current))
3551 : 0 : goto out_unlock;
3552 [ # # ]: 0 : if (vma->anon_vma)
3553 [ # # ]: 0 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3554 : 0 : vm_lock_anon_vma(mm, avc->anon_vma);
3555 : : }
3556 : :
3557 : : return 0;
3558 : :
3559 : 0 : out_unlock:
3560 : 0 : mm_drop_all_locks(mm);
3561 : 0 : return -EINTR;
3562 : : }
3563 : :
3564 : 0 : static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
3565 : : {
3566 [ # # ]: 0 : if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) {
3567 : : /*
3568 : : * The LSB of head.next can't change to 0 from under
3569 : : * us because we hold the mm_all_locks_mutex.
3570 : : *
3571 : : * We must however clear the bitflag before unlocking
3572 : : * the vma so the users using the anon_vma->rb_root will
3573 : : * never see our bitflag.
3574 : : *
3575 : : * No need of atomic instructions here, head.next
3576 : : * can't change from under us until we release the
3577 : : * anon_vma->root->rwsem.
3578 : : */
3579 [ # # ]: 0 : if (!__test_and_clear_bit(0, (unsigned long *)
3580 : 0 : &anon_vma->root->rb_root.rb_root.rb_node))
3581 : 0 : BUG();
3582 : 0 : anon_vma_unlock_write(anon_vma);
3583 : : }
3584 : 0 : }
3585 : :
3586 : 0 : static void vm_unlock_mapping(struct address_space *mapping)
3587 : : {
3588 [ # # ]: 0 : if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3589 : : /*
3590 : : * AS_MM_ALL_LOCKS can't change to 0 from under us
3591 : : * because we hold the mm_all_locks_mutex.
3592 : : */
3593 : 0 : i_mmap_unlock_write(mapping);
3594 [ # # ]: 0 : if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
3595 : : &mapping->flags))
3596 : 0 : BUG();
3597 : : }
3598 : 0 : }
3599 : :
3600 : : /*
3601 : : * The mmap_sem cannot be released by the caller until
3602 : : * mm_drop_all_locks() returns.
3603 : : */
3604 : 0 : void mm_drop_all_locks(struct mm_struct *mm)
3605 : : {
3606 : 0 : struct vm_area_struct *vma;
3607 : 0 : struct anon_vma_chain *avc;
3608 : :
3609 [ # # ]: 0 : BUG_ON(down_read_trylock(&mm->mmap_sem));
3610 [ # # ]: 0 : BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
3611 : :
3612 [ # # ]: 0 : for (vma = mm->mmap; vma; vma = vma->vm_next) {
3613 [ # # ]: 0 : if (vma->anon_vma)
3614 [ # # ]: 0 : list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3615 : 0 : vm_unlock_anon_vma(avc->anon_vma);
3616 [ # # # # ]: 0 : if (vma->vm_file && vma->vm_file->f_mapping)
3617 : 0 : vm_unlock_mapping(vma->vm_file->f_mapping);
3618 : : }
3619 : :
3620 : 0 : mutex_unlock(&mm_all_locks_mutex);
3621 : 0 : }
3622 : :
3623 : : /*
3624 : : * initialise the percpu counter for VM
3625 : : */
3626 : 21 : void __init mmap_init(void)
3627 : : {
3628 : 21 : int ret;
3629 : :
3630 : 21 : ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
3631 : 21 : VM_BUG_ON(ret);
3632 : 21 : }
3633 : :
3634 : : /*
3635 : : * Initialise sysctl_user_reserve_kbytes.
3636 : : *
3637 : : * This is intended to prevent a user from starting a single memory hogging
3638 : : * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
3639 : : * mode.
3640 : : *
3641 : : * The default value is min(3% of free memory, 128MB)
3642 : : * 128MB is enough to recover with sshd/login, bash, and top/kill.
3643 : : */
3644 : 21 : static int init_user_reserve(void)
3645 : : {
3646 : 21 : unsigned long free_kbytes;
3647 : :
3648 : 21 : free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3649 : :
3650 : 21 : sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
3651 : 21 : return 0;
3652 : : }
3653 : : subsys_initcall(init_user_reserve);
3654 : :
3655 : : /*
3656 : : * Initialise sysctl_admin_reserve_kbytes.
3657 : : *
3658 : : * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
3659 : : * to log in and kill a memory hogging process.
3660 : : *
3661 : : * Systems with more than 256MB will reserve 8MB, enough to recover
3662 : : * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
3663 : : * only reserve 3% of free pages by default.
3664 : : */
3665 : 21 : static int init_admin_reserve(void)
3666 : : {
3667 : 21 : unsigned long free_kbytes;
3668 : :
3669 : 21 : free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3670 : :
3671 : 21 : sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
3672 : 21 : return 0;
3673 : : }
3674 : : subsys_initcall(init_admin_reserve);
3675 : :
3676 : : /*
3677 : : * Reinititalise user and admin reserves if memory is added or removed.
3678 : : *
3679 : : * The default user reserve max is 128MB, and the default max for the
3680 : : * admin reserve is 8MB. These are usually, but not always, enough to
3681 : : * enable recovery from a memory hogging process using login/sshd, a shell,
3682 : : * and tools like top. It may make sense to increase or even disable the
3683 : : * reserve depending on the existence of swap or variations in the recovery
3684 : : * tools. So, the admin may have changed them.
3685 : : *
3686 : : * If memory is added and the reserves have been eliminated or increased above
3687 : : * the default max, then we'll trust the admin.
3688 : : *
3689 : : * If memory is removed and there isn't enough free memory, then we
3690 : : * need to reset the reserves.
3691 : : *
3692 : : * Otherwise keep the reserve set by the admin.
3693 : : */
3694 : : static int reserve_mem_notifier(struct notifier_block *nb,
3695 : : unsigned long action, void *data)
3696 : : {
3697 : : unsigned long tmp, free_kbytes;
3698 : :
3699 : : switch (action) {
3700 : : case MEM_ONLINE:
3701 : : /* Default max is 128MB. Leave alone if modified by operator. */
3702 : : tmp = sysctl_user_reserve_kbytes;
3703 : : if (0 < tmp && tmp < (1UL << 17))
3704 : : init_user_reserve();
3705 : :
3706 : : /* Default max is 8MB. Leave alone if modified by operator. */
3707 : : tmp = sysctl_admin_reserve_kbytes;
3708 : : if (0 < tmp && tmp < (1UL << 13))
3709 : : init_admin_reserve();
3710 : :
3711 : : break;
3712 : : case MEM_OFFLINE:
3713 : : free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3714 : :
3715 : : if (sysctl_user_reserve_kbytes > free_kbytes) {
3716 : : init_user_reserve();
3717 : : pr_info("vm.user_reserve_kbytes reset to %lu\n",
3718 : : sysctl_user_reserve_kbytes);
3719 : : }
3720 : :
3721 : : if (sysctl_admin_reserve_kbytes > free_kbytes) {
3722 : : init_admin_reserve();
3723 : : pr_info("vm.admin_reserve_kbytes reset to %lu\n",
3724 : : sysctl_admin_reserve_kbytes);
3725 : : }
3726 : : break;
3727 : : default:
3728 : : break;
3729 : : }
3730 : : return NOTIFY_OK;
3731 : : }
3732 : :
3733 : : static struct notifier_block reserve_mem_nb = {
3734 : : .notifier_call = reserve_mem_notifier,
3735 : : };
3736 : :
3737 : 21 : static int __meminit init_reserve_notifier(void)
3738 : : {
3739 : 21 : if (register_hotmemory_notifier(&reserve_mem_nb))
3740 : : pr_err("Failed registering memory add/remove notifier for admin reserve\n");
3741 : :
3742 : 21 : return 0;
3743 : : }
3744 : : subsys_initcall(init_reserve_notifier);
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