6 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/backing-dev.h>
15 #include <linux/vmacache.h>
16 #include <linux/shm.h>
17 #include <linux/mman.h>
18 #include <linux/pagemap.h>
19 #include <linux/swap.h>
20 #include <linux/syscalls.h>
21 #include <linux/capability.h>
22 #include <linux/init.h>
23 #include <linux/file.h>
25 #include <linux/personality.h>
26 #include <linux/security.h>
27 #include <linux/hugetlb.h>
28 #include <linux/shmem_fs.h>
29 #include <linux/profile.h>
30 #include <linux/export.h>
31 #include <linux/mount.h>
32 #include <linux/mempolicy.h>
33 #include <linux/rmap.h>
34 #include <linux/mmu_notifier.h>
35 #include <linux/mmdebug.h>
36 #include <linux/perf_event.h>
37 #include <linux/audit.h>
38 #include <linux/khugepaged.h>
39 #include <linux/uprobes.h>
40 #include <linux/rbtree_augmented.h>
41 #include <linux/notifier.h>
42 #include <linux/memory.h>
43 #include <linux/printk.h>
44 #include <linux/userfaultfd_k.h>
45 #include <linux/moduleparam.h>
46 #include <linux/pkeys.h>
47 #include <linux/oom.h>
49 #include <linux/uaccess.h>
50 #include <asm/cacheflush.h>
52 #include <asm/mmu_context.h>
56 #ifndef arch_mmap_check
57 #define arch_mmap_check(addr, len, flags) (0)
60 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
61 const int mmap_rnd_bits_min
= CONFIG_ARCH_MMAP_RND_BITS_MIN
;
62 const int mmap_rnd_bits_max
= CONFIG_ARCH_MMAP_RND_BITS_MAX
;
63 int mmap_rnd_bits __read_mostly
= CONFIG_ARCH_MMAP_RND_BITS
;
65 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
66 const int mmap_rnd_compat_bits_min
= CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN
;
67 const int mmap_rnd_compat_bits_max
= CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX
;
68 int mmap_rnd_compat_bits __read_mostly
= CONFIG_ARCH_MMAP_RND_COMPAT_BITS
;
71 static bool ignore_rlimit_data
;
72 core_param(ignore_rlimit_data
, ignore_rlimit_data
, bool, 0644);
74 static void unmap_region(struct mm_struct
*mm
,
75 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
76 unsigned long start
, unsigned long end
);
78 /* description of effects of mapping type and prot in current implementation.
79 * this is due to the limited x86 page protection hardware. The expected
80 * behavior is in parens:
83 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
84 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
85 * w: (no) no w: (no) no w: (yes) yes w: (no) no
86 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
88 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
89 * w: (no) no w: (no) no w: (copy) copy w: (no) no
90 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
92 * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
98 pgprot_t protection_map
[16] __ro_after_init
= {
99 __P000
, __P001
, __P010
, __P011
, __P100
, __P101
, __P110
, __P111
,
100 __S000
, __S001
, __S010
, __S011
, __S100
, __S101
, __S110
, __S111
103 #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT
104 static inline pgprot_t
arch_filter_pgprot(pgprot_t prot
)
110 pgprot_t
vm_get_page_prot(unsigned long vm_flags
)
112 pgprot_t ret
= __pgprot(pgprot_val(protection_map
[vm_flags
&
113 (VM_READ
|VM_WRITE
|VM_EXEC
|VM_SHARED
)]) |
114 pgprot_val(arch_vm_get_page_prot(vm_flags
)));
116 return arch_filter_pgprot(ret
);
118 EXPORT_SYMBOL(vm_get_page_prot
);
120 static pgprot_t
vm_pgprot_modify(pgprot_t oldprot
, unsigned long vm_flags
)
122 return pgprot_modify(oldprot
, vm_get_page_prot(vm_flags
));
125 /* Update vma->vm_page_prot to reflect vma->vm_flags. */
126 void vma_set_page_prot(struct vm_area_struct
*vma
)
128 unsigned long vm_flags
= vma
->vm_flags
;
129 pgprot_t vm_page_prot
;
131 vm_page_prot
= vm_pgprot_modify(vma
->vm_page_prot
, vm_flags
);
132 if (vma_wants_writenotify(vma
, vm_page_prot
)) {
133 vm_flags
&= ~VM_SHARED
;
134 vm_page_prot
= vm_pgprot_modify(vm_page_prot
, vm_flags
);
136 /* remove_protection_ptes reads vma->vm_page_prot without mmap_sem */
137 WRITE_ONCE(vma
->vm_page_prot
, vm_page_prot
);
141 * Requires inode->i_mapping->i_mmap_rwsem
143 static void __remove_shared_vm_struct(struct vm_area_struct
*vma
,
144 struct file
*file
, struct address_space
*mapping
)
146 if (vma
->vm_flags
& VM_DENYWRITE
)
147 atomic_inc(&file_inode(file
)->i_writecount
);
148 if (vma
->vm_flags
& VM_SHARED
)
149 mapping_unmap_writable(mapping
);
151 flush_dcache_mmap_lock(mapping
);
152 vma_interval_tree_remove(vma
, &mapping
->i_mmap
);
153 flush_dcache_mmap_unlock(mapping
);
157 * Unlink a file-based vm structure from its interval tree, to hide
158 * vma from rmap and vmtruncate before freeing its page tables.
160 void unlink_file_vma(struct vm_area_struct
*vma
)
162 struct file
*file
= vma
->vm_file
;
165 struct address_space
*mapping
= file
->f_mapping
;
166 i_mmap_lock_write(mapping
);
167 __remove_shared_vm_struct(vma
, file
, mapping
);
168 i_mmap_unlock_write(mapping
);
173 * Close a vm structure and free it, returning the next.
175 static struct vm_area_struct
*remove_vma(struct vm_area_struct
*vma
)
177 struct vm_area_struct
*next
= vma
->vm_next
;
180 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
181 vma
->vm_ops
->close(vma
);
184 mpol_put(vma_policy(vma
));
185 kmem_cache_free(vm_area_cachep
, vma
);
189 static int do_brk(unsigned long addr
, unsigned long len
, struct list_head
*uf
);
191 SYSCALL_DEFINE1(brk
, unsigned long, brk
)
193 unsigned long retval
;
194 unsigned long newbrk
, oldbrk
;
195 struct mm_struct
*mm
= current
->mm
;
196 struct vm_area_struct
*next
;
197 unsigned long min_brk
;
201 if (down_write_killable(&mm
->mmap_sem
))
204 #ifdef CONFIG_COMPAT_BRK
206 * CONFIG_COMPAT_BRK can still be overridden by setting
207 * randomize_va_space to 2, which will still cause mm->start_brk
208 * to be arbitrarily shifted
210 if (current
->brk_randomized
)
211 min_brk
= mm
->start_brk
;
213 min_brk
= mm
->end_data
;
215 min_brk
= mm
->start_brk
;
221 * Check against rlimit here. If this check is done later after the test
222 * of oldbrk with newbrk then it can escape the test and let the data
223 * segment grow beyond its set limit the in case where the limit is
224 * not page aligned -Ram Gupta
226 if (check_data_rlimit(rlimit(RLIMIT_DATA
), brk
, mm
->start_brk
,
227 mm
->end_data
, mm
->start_data
))
230 newbrk
= PAGE_ALIGN(brk
);
231 oldbrk
= PAGE_ALIGN(mm
->brk
);
232 if (oldbrk
== newbrk
)
235 /* Always allow shrinking brk. */
236 if (brk
<= mm
->brk
) {
237 if (!do_munmap(mm
, newbrk
, oldbrk
-newbrk
, &uf
))
242 /* Check against existing mmap mappings. */
243 next
= find_vma(mm
, oldbrk
);
244 if (next
&& newbrk
+ PAGE_SIZE
> vm_start_gap(next
))
247 /* Ok, looks good - let it rip. */
248 if (do_brk(oldbrk
, newbrk
-oldbrk
, &uf
) < 0)
253 populate
= newbrk
> oldbrk
&& (mm
->def_flags
& VM_LOCKED
) != 0;
254 up_write(&mm
->mmap_sem
);
255 userfaultfd_unmap_complete(mm
, &uf
);
257 mm_populate(oldbrk
, newbrk
- oldbrk
);
262 up_write(&mm
->mmap_sem
);
266 static long vma_compute_subtree_gap(struct vm_area_struct
*vma
)
268 unsigned long max
, prev_end
, subtree_gap
;
271 * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
272 * allow two stack_guard_gaps between them here, and when choosing
273 * an unmapped area; whereas when expanding we only require one.
274 * That's a little inconsistent, but keeps the code here simpler.
276 max
= vm_start_gap(vma
);
278 prev_end
= vm_end_gap(vma
->vm_prev
);
284 if (vma
->vm_rb
.rb_left
) {
285 subtree_gap
= rb_entry(vma
->vm_rb
.rb_left
,
286 struct vm_area_struct
, vm_rb
)->rb_subtree_gap
;
287 if (subtree_gap
> max
)
290 if (vma
->vm_rb
.rb_right
) {
291 subtree_gap
= rb_entry(vma
->vm_rb
.rb_right
,
292 struct vm_area_struct
, vm_rb
)->rb_subtree_gap
;
293 if (subtree_gap
> max
)
299 #ifdef CONFIG_DEBUG_VM_RB
300 static int browse_rb(struct mm_struct
*mm
)
302 struct rb_root
*root
= &mm
->mm_rb
;
303 int i
= 0, j
, bug
= 0;
304 struct rb_node
*nd
, *pn
= NULL
;
305 unsigned long prev
= 0, pend
= 0;
307 for (nd
= rb_first(root
); nd
; nd
= rb_next(nd
)) {
308 struct vm_area_struct
*vma
;
309 vma
= rb_entry(nd
, struct vm_area_struct
, vm_rb
);
310 if (vma
->vm_start
< prev
) {
311 pr_emerg("vm_start %lx < prev %lx\n",
312 vma
->vm_start
, prev
);
315 if (vma
->vm_start
< pend
) {
316 pr_emerg("vm_start %lx < pend %lx\n",
317 vma
->vm_start
, pend
);
320 if (vma
->vm_start
> vma
->vm_end
) {
321 pr_emerg("vm_start %lx > vm_end %lx\n",
322 vma
->vm_start
, vma
->vm_end
);
325 spin_lock(&mm
->page_table_lock
);
326 if (vma
->rb_subtree_gap
!= vma_compute_subtree_gap(vma
)) {
327 pr_emerg("free gap %lx, correct %lx\n",
329 vma_compute_subtree_gap(vma
));
332 spin_unlock(&mm
->page_table_lock
);
335 prev
= vma
->vm_start
;
339 for (nd
= pn
; nd
; nd
= rb_prev(nd
))
342 pr_emerg("backwards %d, forwards %d\n", j
, i
);
348 static void validate_mm_rb(struct rb_root
*root
, struct vm_area_struct
*ignore
)
352 for (nd
= rb_first(root
); nd
; nd
= rb_next(nd
)) {
353 struct vm_area_struct
*vma
;
354 vma
= rb_entry(nd
, struct vm_area_struct
, vm_rb
);
355 VM_BUG_ON_VMA(vma
!= ignore
&&
356 vma
->rb_subtree_gap
!= vma_compute_subtree_gap(vma
),
361 static void validate_mm(struct mm_struct
*mm
)
365 unsigned long highest_address
= 0;
366 struct vm_area_struct
*vma
= mm
->mmap
;
369 struct anon_vma
*anon_vma
= vma
->anon_vma
;
370 struct anon_vma_chain
*avc
;
373 anon_vma_lock_read(anon_vma
);
374 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
375 anon_vma_interval_tree_verify(avc
);
376 anon_vma_unlock_read(anon_vma
);
379 highest_address
= vm_end_gap(vma
);
383 if (i
!= mm
->map_count
) {
384 pr_emerg("map_count %d vm_next %d\n", mm
->map_count
, i
);
387 if (highest_address
!= mm
->highest_vm_end
) {
388 pr_emerg("mm->highest_vm_end %lx, found %lx\n",
389 mm
->highest_vm_end
, highest_address
);
393 if (i
!= mm
->map_count
) {
395 pr_emerg("map_count %d rb %d\n", mm
->map_count
, i
);
398 VM_BUG_ON_MM(bug
, mm
);
401 #define validate_mm_rb(root, ignore) do { } while (0)
402 #define validate_mm(mm) do { } while (0)
405 RB_DECLARE_CALLBACKS(static, vma_gap_callbacks
, struct vm_area_struct
, vm_rb
,
406 unsigned long, rb_subtree_gap
, vma_compute_subtree_gap
)
409 * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
410 * vma->vm_prev->vm_end values changed, without modifying the vma's position
413 static void vma_gap_update(struct vm_area_struct
*vma
)
416 * As it turns out, RB_DECLARE_CALLBACKS() already created a callback
417 * function that does exacltly what we want.
419 vma_gap_callbacks_propagate(&vma
->vm_rb
, NULL
);
422 static inline void vma_rb_insert(struct vm_area_struct
*vma
,
423 struct rb_root
*root
)
425 /* All rb_subtree_gap values must be consistent prior to insertion */
426 validate_mm_rb(root
, NULL
);
428 rb_insert_augmented(&vma
->vm_rb
, root
, &vma_gap_callbacks
);
431 static void __vma_rb_erase(struct vm_area_struct
*vma
, struct rb_root
*root
)
434 * Note rb_erase_augmented is a fairly large inline function,
435 * so make sure we instantiate it only once with our desired
436 * augmented rbtree callbacks.
438 rb_erase_augmented(&vma
->vm_rb
, root
, &vma_gap_callbacks
);
441 static __always_inline
void vma_rb_erase_ignore(struct vm_area_struct
*vma
,
442 struct rb_root
*root
,
443 struct vm_area_struct
*ignore
)
446 * All rb_subtree_gap values must be consistent prior to erase,
447 * with the possible exception of the "next" vma being erased if
448 * next->vm_start was reduced.
450 validate_mm_rb(root
, ignore
);
452 __vma_rb_erase(vma
, root
);
455 static __always_inline
void vma_rb_erase(struct vm_area_struct
*vma
,
456 struct rb_root
*root
)
459 * All rb_subtree_gap values must be consistent prior to erase,
460 * with the possible exception of the vma being erased.
462 validate_mm_rb(root
, vma
);
464 __vma_rb_erase(vma
, root
);
468 * vma has some anon_vma assigned, and is already inserted on that
469 * anon_vma's interval trees.
471 * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
472 * vma must be removed from the anon_vma's interval trees using
473 * anon_vma_interval_tree_pre_update_vma().
475 * After the update, the vma will be reinserted using
476 * anon_vma_interval_tree_post_update_vma().
478 * The entire update must be protected by exclusive mmap_sem and by
479 * the root anon_vma's mutex.
482 anon_vma_interval_tree_pre_update_vma(struct vm_area_struct
*vma
)
484 struct anon_vma_chain
*avc
;
486 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
487 anon_vma_interval_tree_remove(avc
, &avc
->anon_vma
->rb_root
);
491 anon_vma_interval_tree_post_update_vma(struct vm_area_struct
*vma
)
493 struct anon_vma_chain
*avc
;
495 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
496 anon_vma_interval_tree_insert(avc
, &avc
->anon_vma
->rb_root
);
499 static int find_vma_links(struct mm_struct
*mm
, unsigned long addr
,
500 unsigned long end
, struct vm_area_struct
**pprev
,
501 struct rb_node
***rb_link
, struct rb_node
**rb_parent
)
503 struct rb_node
**__rb_link
, *__rb_parent
, *rb_prev
;
505 __rb_link
= &mm
->mm_rb
.rb_node
;
506 rb_prev
= __rb_parent
= NULL
;
509 struct vm_area_struct
*vma_tmp
;
511 __rb_parent
= *__rb_link
;
512 vma_tmp
= rb_entry(__rb_parent
, struct vm_area_struct
, vm_rb
);
514 if (vma_tmp
->vm_end
> addr
) {
515 /* Fail if an existing vma overlaps the area */
516 if (vma_tmp
->vm_start
< end
)
518 __rb_link
= &__rb_parent
->rb_left
;
520 rb_prev
= __rb_parent
;
521 __rb_link
= &__rb_parent
->rb_right
;
527 *pprev
= rb_entry(rb_prev
, struct vm_area_struct
, vm_rb
);
528 *rb_link
= __rb_link
;
529 *rb_parent
= __rb_parent
;
533 static unsigned long count_vma_pages_range(struct mm_struct
*mm
,
534 unsigned long addr
, unsigned long end
)
536 unsigned long nr_pages
= 0;
537 struct vm_area_struct
*vma
;
539 /* Find first overlaping mapping */
540 vma
= find_vma_intersection(mm
, addr
, end
);
544 nr_pages
= (min(end
, vma
->vm_end
) -
545 max(addr
, vma
->vm_start
)) >> PAGE_SHIFT
;
547 /* Iterate over the rest of the overlaps */
548 for (vma
= vma
->vm_next
; vma
; vma
= vma
->vm_next
) {
549 unsigned long overlap_len
;
551 if (vma
->vm_start
> end
)
554 overlap_len
= min(end
, vma
->vm_end
) - vma
->vm_start
;
555 nr_pages
+= overlap_len
>> PAGE_SHIFT
;
561 void __vma_link_rb(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
562 struct rb_node
**rb_link
, struct rb_node
*rb_parent
)
564 /* Update tracking information for the gap following the new vma. */
566 vma_gap_update(vma
->vm_next
);
568 mm
->highest_vm_end
= vm_end_gap(vma
);
571 * vma->vm_prev wasn't known when we followed the rbtree to find the
572 * correct insertion point for that vma. As a result, we could not
573 * update the vma vm_rb parents rb_subtree_gap values on the way down.
574 * So, we first insert the vma with a zero rb_subtree_gap value
575 * (to be consistent with what we did on the way down), and then
576 * immediately update the gap to the correct value. Finally we
577 * rebalance the rbtree after all augmented values have been set.
579 rb_link_node(&vma
->vm_rb
, rb_parent
, rb_link
);
580 vma
->rb_subtree_gap
= 0;
582 vma_rb_insert(vma
, &mm
->mm_rb
);
585 static void __vma_link_file(struct vm_area_struct
*vma
)
591 struct address_space
*mapping
= file
->f_mapping
;
593 if (vma
->vm_flags
& VM_DENYWRITE
)
594 atomic_dec(&file_inode(file
)->i_writecount
);
595 if (vma
->vm_flags
& VM_SHARED
)
596 atomic_inc(&mapping
->i_mmap_writable
);
598 flush_dcache_mmap_lock(mapping
);
599 vma_interval_tree_insert(vma
, &mapping
->i_mmap
);
600 flush_dcache_mmap_unlock(mapping
);
605 __vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
606 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
607 struct rb_node
*rb_parent
)
609 __vma_link_list(mm
, vma
, prev
, rb_parent
);
610 __vma_link_rb(mm
, vma
, rb_link
, rb_parent
);
613 static void vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
614 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
615 struct rb_node
*rb_parent
)
617 struct address_space
*mapping
= NULL
;
620 mapping
= vma
->vm_file
->f_mapping
;
621 i_mmap_lock_write(mapping
);
624 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
625 __vma_link_file(vma
);
628 i_mmap_unlock_write(mapping
);
635 * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
636 * mm's list and rbtree. It has already been inserted into the interval tree.
638 static void __insert_vm_struct(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
640 struct vm_area_struct
*prev
;
641 struct rb_node
**rb_link
, *rb_parent
;
643 if (find_vma_links(mm
, vma
->vm_start
, vma
->vm_end
,
644 &prev
, &rb_link
, &rb_parent
))
646 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
650 static __always_inline
void __vma_unlink_common(struct mm_struct
*mm
,
651 struct vm_area_struct
*vma
,
652 struct vm_area_struct
*prev
,
654 struct vm_area_struct
*ignore
)
656 struct vm_area_struct
*next
;
658 vma_rb_erase_ignore(vma
, &mm
->mm_rb
, ignore
);
661 prev
->vm_next
= next
;
665 prev
->vm_next
= next
;
670 next
->vm_prev
= prev
;
673 vmacache_invalidate(mm
);
676 static inline void __vma_unlink_prev(struct mm_struct
*mm
,
677 struct vm_area_struct
*vma
,
678 struct vm_area_struct
*prev
)
680 __vma_unlink_common(mm
, vma
, prev
, true, vma
);
684 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
685 * is already present in an i_mmap tree without adjusting the tree.
686 * The following helper function should be used when such adjustments
687 * are necessary. The "insert" vma (if any) is to be inserted
688 * before we drop the necessary locks.
690 int __vma_adjust(struct vm_area_struct
*vma
, unsigned long start
,
691 unsigned long end
, pgoff_t pgoff
, struct vm_area_struct
*insert
,
692 struct vm_area_struct
*expand
)
694 struct mm_struct
*mm
= vma
->vm_mm
;
695 struct vm_area_struct
*next
= vma
->vm_next
, *orig_vma
= vma
;
696 struct address_space
*mapping
= NULL
;
697 struct rb_root_cached
*root
= NULL
;
698 struct anon_vma
*anon_vma
= NULL
;
699 struct file
*file
= vma
->vm_file
;
700 bool start_changed
= false, end_changed
= false;
701 long adjust_next
= 0;
704 if (next
&& !insert
) {
705 struct vm_area_struct
*exporter
= NULL
, *importer
= NULL
;
707 if (end
>= next
->vm_end
) {
709 * vma expands, overlapping all the next, and
710 * perhaps the one after too (mprotect case 6).
711 * The only other cases that gets here are
712 * case 1, case 7 and case 8.
714 if (next
== expand
) {
716 * The only case where we don't expand "vma"
717 * and we expand "next" instead is case 8.
719 VM_WARN_ON(end
!= next
->vm_end
);
721 * remove_next == 3 means we're
722 * removing "vma" and that to do so we
723 * swapped "vma" and "next".
726 VM_WARN_ON(file
!= next
->vm_file
);
729 VM_WARN_ON(expand
!= vma
);
731 * case 1, 6, 7, remove_next == 2 is case 6,
732 * remove_next == 1 is case 1 or 7.
734 remove_next
= 1 + (end
> next
->vm_end
);
735 VM_WARN_ON(remove_next
== 2 &&
736 end
!= next
->vm_next
->vm_end
);
737 VM_WARN_ON(remove_next
== 1 &&
738 end
!= next
->vm_end
);
739 /* trim end to next, for case 6 first pass */
747 * If next doesn't have anon_vma, import from vma after
748 * next, if the vma overlaps with it.
750 if (remove_next
== 2 && !next
->anon_vma
)
751 exporter
= next
->vm_next
;
753 } else if (end
> next
->vm_start
) {
755 * vma expands, overlapping part of the next:
756 * mprotect case 5 shifting the boundary up.
758 adjust_next
= (end
- next
->vm_start
) >> PAGE_SHIFT
;
761 VM_WARN_ON(expand
!= importer
);
762 } else if (end
< vma
->vm_end
) {
764 * vma shrinks, and !insert tells it's not
765 * split_vma inserting another: so it must be
766 * mprotect case 4 shifting the boundary down.
768 adjust_next
= -((vma
->vm_end
- end
) >> PAGE_SHIFT
);
771 VM_WARN_ON(expand
!= importer
);
775 * Easily overlooked: when mprotect shifts the boundary,
776 * make sure the expanding vma has anon_vma set if the
777 * shrinking vma had, to cover any anon pages imported.
779 if (exporter
&& exporter
->anon_vma
&& !importer
->anon_vma
) {
782 importer
->anon_vma
= exporter
->anon_vma
;
783 error
= anon_vma_clone(importer
, exporter
);
789 vma_adjust_trans_huge(orig_vma
, start
, end
, adjust_next
);
792 mapping
= file
->f_mapping
;
793 root
= &mapping
->i_mmap
;
794 uprobe_munmap(vma
, vma
->vm_start
, vma
->vm_end
);
797 uprobe_munmap(next
, next
->vm_start
, next
->vm_end
);
799 i_mmap_lock_write(mapping
);
802 * Put into interval tree now, so instantiated pages
803 * are visible to arm/parisc __flush_dcache_page
804 * throughout; but we cannot insert into address
805 * space until vma start or end is updated.
807 __vma_link_file(insert
);
811 anon_vma
= vma
->anon_vma
;
812 if (!anon_vma
&& adjust_next
)
813 anon_vma
= next
->anon_vma
;
815 VM_WARN_ON(adjust_next
&& next
->anon_vma
&&
816 anon_vma
!= next
->anon_vma
);
817 anon_vma_lock_write(anon_vma
);
818 anon_vma_interval_tree_pre_update_vma(vma
);
820 anon_vma_interval_tree_pre_update_vma(next
);
824 flush_dcache_mmap_lock(mapping
);
825 vma_interval_tree_remove(vma
, root
);
827 vma_interval_tree_remove(next
, root
);
830 if (start
!= vma
->vm_start
) {
831 vma
->vm_start
= start
;
832 start_changed
= true;
834 if (end
!= vma
->vm_end
) {
838 vma
->vm_pgoff
= pgoff
;
840 next
->vm_start
+= adjust_next
<< PAGE_SHIFT
;
841 next
->vm_pgoff
+= adjust_next
;
846 vma_interval_tree_insert(next
, root
);
847 vma_interval_tree_insert(vma
, root
);
848 flush_dcache_mmap_unlock(mapping
);
853 * vma_merge has merged next into vma, and needs
854 * us to remove next before dropping the locks.
856 if (remove_next
!= 3)
857 __vma_unlink_prev(mm
, next
, vma
);
860 * vma is not before next if they've been
863 * pre-swap() next->vm_start was reduced so
864 * tell validate_mm_rb to ignore pre-swap()
865 * "next" (which is stored in post-swap()
868 __vma_unlink_common(mm
, next
, NULL
, false, vma
);
870 __remove_shared_vm_struct(next
, file
, mapping
);
873 * split_vma has split insert from vma, and needs
874 * us to insert it before dropping the locks
875 * (it may either follow vma or precede it).
877 __insert_vm_struct(mm
, insert
);
883 mm
->highest_vm_end
= vm_end_gap(vma
);
884 else if (!adjust_next
)
885 vma_gap_update(next
);
890 anon_vma_interval_tree_post_update_vma(vma
);
892 anon_vma_interval_tree_post_update_vma(next
);
893 anon_vma_unlock_write(anon_vma
);
896 i_mmap_unlock_write(mapping
);
907 uprobe_munmap(next
, next
->vm_start
, next
->vm_end
);
911 anon_vma_merge(vma
, next
);
913 mpol_put(vma_policy(next
));
914 kmem_cache_free(vm_area_cachep
, next
);
916 * In mprotect's case 6 (see comments on vma_merge),
917 * we must remove another next too. It would clutter
918 * up the code too much to do both in one go.
920 if (remove_next
!= 3) {
922 * If "next" was removed and vma->vm_end was
923 * expanded (up) over it, in turn
924 * "next->vm_prev->vm_end" changed and the
925 * "vma->vm_next" gap must be updated.
930 * For the scope of the comment "next" and
931 * "vma" considered pre-swap(): if "vma" was
932 * removed, next->vm_start was expanded (down)
933 * over it and the "next" gap must be updated.
934 * Because of the swap() the post-swap() "vma"
935 * actually points to pre-swap() "next"
936 * (post-swap() "next" as opposed is now a
941 if (remove_next
== 2) {
947 vma_gap_update(next
);
950 * If remove_next == 2 we obviously can't
953 * If remove_next == 3 we can't reach this
954 * path because pre-swap() next is always not
955 * NULL. pre-swap() "next" is not being
956 * removed and its next->vm_end is not altered
957 * (and furthermore "end" already matches
958 * next->vm_end in remove_next == 3).
960 * We reach this only in the remove_next == 1
961 * case if the "next" vma that was removed was
962 * the highest vma of the mm. However in such
963 * case next->vm_end == "end" and the extended
964 * "vma" has vma->vm_end == next->vm_end so
965 * mm->highest_vm_end doesn't need any update
966 * in remove_next == 1 case.
968 VM_WARN_ON(mm
->highest_vm_end
!= vm_end_gap(vma
));
980 * If the vma has a ->close operation then the driver probably needs to release
981 * per-vma resources, so we don't attempt to merge those.
983 static inline int is_mergeable_vma(struct vm_area_struct
*vma
,
984 struct file
*file
, unsigned long vm_flags
,
985 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
988 * VM_SOFTDIRTY should not prevent from VMA merging, if we
989 * match the flags but dirty bit -- the caller should mark
990 * merged VMA as dirty. If dirty bit won't be excluded from
991 * comparison, we increase pressue on the memory system forcing
992 * the kernel to generate new VMAs when old one could be
995 if ((vma
->vm_flags
^ vm_flags
) & ~VM_SOFTDIRTY
)
997 if (vma
->vm_file
!= file
)
999 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
1001 if (!is_mergeable_vm_userfaultfd_ctx(vma
, vm_userfaultfd_ctx
))
1006 static inline int is_mergeable_anon_vma(struct anon_vma
*anon_vma1
,
1007 struct anon_vma
*anon_vma2
,
1008 struct vm_area_struct
*vma
)
1011 * The list_is_singular() test is to avoid merging VMA cloned from
1012 * parents. This can improve scalability caused by anon_vma lock.
1014 if ((!anon_vma1
|| !anon_vma2
) && (!vma
||
1015 list_is_singular(&vma
->anon_vma_chain
)))
1017 return anon_vma1
== anon_vma2
;
1021 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
1022 * in front of (at a lower virtual address and file offset than) the vma.
1024 * We cannot merge two vmas if they have differently assigned (non-NULL)
1025 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
1027 * We don't check here for the merged mmap wrapping around the end of pagecache
1028 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
1029 * wrap, nor mmaps which cover the final page at index -1UL.
1032 can_vma_merge_before(struct vm_area_struct
*vma
, unsigned long vm_flags
,
1033 struct anon_vma
*anon_vma
, struct file
*file
,
1035 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
1037 if (is_mergeable_vma(vma
, file
, vm_flags
, vm_userfaultfd_ctx
) &&
1038 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
, vma
)) {
1039 if (vma
->vm_pgoff
== vm_pgoff
)
1046 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
1047 * beyond (at a higher virtual address and file offset than) the vma.
1049 * We cannot merge two vmas if they have differently assigned (non-NULL)
1050 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
1053 can_vma_merge_after(struct vm_area_struct
*vma
, unsigned long vm_flags
,
1054 struct anon_vma
*anon_vma
, struct file
*file
,
1056 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
1058 if (is_mergeable_vma(vma
, file
, vm_flags
, vm_userfaultfd_ctx
) &&
1059 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
, vma
)) {
1061 vm_pglen
= vma_pages(vma
);
1062 if (vma
->vm_pgoff
+ vm_pglen
== vm_pgoff
)
1069 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
1070 * whether that can be merged with its predecessor or its successor.
1071 * Or both (it neatly fills a hole).
1073 * In most cases - when called for mmap, brk or mremap - [addr,end) is
1074 * certain not to be mapped by the time vma_merge is called; but when
1075 * called for mprotect, it is certain to be already mapped (either at
1076 * an offset within prev, or at the start of next), and the flags of
1077 * this area are about to be changed to vm_flags - and the no-change
1078 * case has already been eliminated.
1080 * The following mprotect cases have to be considered, where AAAA is
1081 * the area passed down from mprotect_fixup, never extending beyond one
1082 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
1084 * AAAA AAAA AAAA AAAA
1085 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
1086 * cannot merge might become might become might become
1087 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
1088 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
1089 * mremap move: PPPPXXXXXXXX 8
1091 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
1092 * might become case 1 below case 2 below case 3 below
1094 * It is important for case 8 that the the vma NNNN overlapping the
1095 * region AAAA is never going to extended over XXXX. Instead XXXX must
1096 * be extended in region AAAA and NNNN must be removed. This way in
1097 * all cases where vma_merge succeeds, the moment vma_adjust drops the
1098 * rmap_locks, the properties of the merged vma will be already
1099 * correct for the whole merged range. Some of those properties like
1100 * vm_page_prot/vm_flags may be accessed by rmap_walks and they must
1101 * be correct for the whole merged range immediately after the
1102 * rmap_locks are released. Otherwise if XXXX would be removed and
1103 * NNNN would be extended over the XXXX range, remove_migration_ptes
1104 * or other rmap walkers (if working on addresses beyond the "end"
1105 * parameter) may establish ptes with the wrong permissions of NNNN
1106 * instead of the right permissions of XXXX.
1108 struct vm_area_struct
*vma_merge(struct mm_struct
*mm
,
1109 struct vm_area_struct
*prev
, unsigned long addr
,
1110 unsigned long end
, unsigned long vm_flags
,
1111 struct anon_vma
*anon_vma
, struct file
*file
,
1112 pgoff_t pgoff
, struct mempolicy
*policy
,
1113 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
)
1115 pgoff_t pglen
= (end
- addr
) >> PAGE_SHIFT
;
1116 struct vm_area_struct
*area
, *next
;
1120 * We later require that vma->vm_flags == vm_flags,
1121 * so this tests vma->vm_flags & VM_SPECIAL, too.
1123 if (vm_flags
& VM_SPECIAL
)
1127 next
= prev
->vm_next
;
1131 if (area
&& area
->vm_end
== end
) /* cases 6, 7, 8 */
1132 next
= next
->vm_next
;
1134 /* verify some invariant that must be enforced by the caller */
1135 VM_WARN_ON(prev
&& addr
<= prev
->vm_start
);
1136 VM_WARN_ON(area
&& end
> area
->vm_end
);
1137 VM_WARN_ON(addr
>= end
);
1140 * Can it merge with the predecessor?
1142 if (prev
&& prev
->vm_end
== addr
&&
1143 mpol_equal(vma_policy(prev
), policy
) &&
1144 can_vma_merge_after(prev
, vm_flags
,
1145 anon_vma
, file
, pgoff
,
1146 vm_userfaultfd_ctx
)) {
1148 * OK, it can. Can we now merge in the successor as well?
1150 if (next
&& end
== next
->vm_start
&&
1151 mpol_equal(policy
, vma_policy(next
)) &&
1152 can_vma_merge_before(next
, vm_flags
,
1155 vm_userfaultfd_ctx
) &&
1156 is_mergeable_anon_vma(prev
->anon_vma
,
1157 next
->anon_vma
, NULL
)) {
1159 err
= __vma_adjust(prev
, prev
->vm_start
,
1160 next
->vm_end
, prev
->vm_pgoff
, NULL
,
1162 } else /* cases 2, 5, 7 */
1163 err
= __vma_adjust(prev
, prev
->vm_start
,
1164 end
, prev
->vm_pgoff
, NULL
, prev
);
1167 khugepaged_enter_vma_merge(prev
, vm_flags
);
1172 * Can this new request be merged in front of next?
1174 if (next
&& end
== next
->vm_start
&&
1175 mpol_equal(policy
, vma_policy(next
)) &&
1176 can_vma_merge_before(next
, vm_flags
,
1177 anon_vma
, file
, pgoff
+pglen
,
1178 vm_userfaultfd_ctx
)) {
1179 if (prev
&& addr
< prev
->vm_end
) /* case 4 */
1180 err
= __vma_adjust(prev
, prev
->vm_start
,
1181 addr
, prev
->vm_pgoff
, NULL
, next
);
1182 else { /* cases 3, 8 */
1183 err
= __vma_adjust(area
, addr
, next
->vm_end
,
1184 next
->vm_pgoff
- pglen
, NULL
, next
);
1186 * In case 3 area is already equal to next and
1187 * this is a noop, but in case 8 "area" has
1188 * been removed and next was expanded over it.
1194 khugepaged_enter_vma_merge(area
, vm_flags
);
1202 * Rough compatbility check to quickly see if it's even worth looking
1203 * at sharing an anon_vma.
1205 * They need to have the same vm_file, and the flags can only differ
1206 * in things that mprotect may change.
1208 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1209 * we can merge the two vma's. For example, we refuse to merge a vma if
1210 * there is a vm_ops->close() function, because that indicates that the
1211 * driver is doing some kind of reference counting. But that doesn't
1212 * really matter for the anon_vma sharing case.
1214 static int anon_vma_compatible(struct vm_area_struct
*a
, struct vm_area_struct
*b
)
1216 return a
->vm_end
== b
->vm_start
&&
1217 mpol_equal(vma_policy(a
), vma_policy(b
)) &&
1218 a
->vm_file
== b
->vm_file
&&
1219 !((a
->vm_flags
^ b
->vm_flags
) & ~(VM_READ
|VM_WRITE
|VM_EXEC
|VM_SOFTDIRTY
)) &&
1220 b
->vm_pgoff
== a
->vm_pgoff
+ ((b
->vm_start
- a
->vm_start
) >> PAGE_SHIFT
);
1224 * Do some basic sanity checking to see if we can re-use the anon_vma
1225 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1226 * the same as 'old', the other will be the new one that is trying
1227 * to share the anon_vma.
1229 * NOTE! This runs with mm_sem held for reading, so it is possible that
1230 * the anon_vma of 'old' is concurrently in the process of being set up
1231 * by another page fault trying to merge _that_. But that's ok: if it
1232 * is being set up, that automatically means that it will be a singleton
1233 * acceptable for merging, so we can do all of this optimistically. But
1234 * we do that READ_ONCE() to make sure that we never re-load the pointer.
1236 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1237 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1238 * is to return an anon_vma that is "complex" due to having gone through
1241 * We also make sure that the two vma's are compatible (adjacent,
1242 * and with the same memory policies). That's all stable, even with just
1243 * a read lock on the mm_sem.
1245 static struct anon_vma
*reusable_anon_vma(struct vm_area_struct
*old
, struct vm_area_struct
*a
, struct vm_area_struct
*b
)
1247 if (anon_vma_compatible(a
, b
)) {
1248 struct anon_vma
*anon_vma
= READ_ONCE(old
->anon_vma
);
1250 if (anon_vma
&& list_is_singular(&old
->anon_vma_chain
))
1257 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1258 * neighbouring vmas for a suitable anon_vma, before it goes off
1259 * to allocate a new anon_vma. It checks because a repetitive
1260 * sequence of mprotects and faults may otherwise lead to distinct
1261 * anon_vmas being allocated, preventing vma merge in subsequent
1264 struct anon_vma
*find_mergeable_anon_vma(struct vm_area_struct
*vma
)
1266 struct anon_vma
*anon_vma
;
1267 struct vm_area_struct
*near
;
1269 near
= vma
->vm_next
;
1273 anon_vma
= reusable_anon_vma(near
, vma
, near
);
1277 near
= vma
->vm_prev
;
1281 anon_vma
= reusable_anon_vma(near
, near
, vma
);
1286 * There's no absolute need to look only at touching neighbours:
1287 * we could search further afield for "compatible" anon_vmas.
1288 * But it would probably just be a waste of time searching,
1289 * or lead to too many vmas hanging off the same anon_vma.
1290 * We're trying to allow mprotect remerging later on,
1291 * not trying to minimize memory used for anon_vmas.
1297 * If a hint addr is less than mmap_min_addr change hint to be as
1298 * low as possible but still greater than mmap_min_addr
1300 static inline unsigned long round_hint_to_min(unsigned long hint
)
1303 if (((void *)hint
!= NULL
) &&
1304 (hint
< mmap_min_addr
))
1305 return PAGE_ALIGN(mmap_min_addr
);
1309 static inline int mlock_future_check(struct mm_struct
*mm
,
1310 unsigned long flags
,
1313 unsigned long locked
, lock_limit
;
1315 /* mlock MCL_FUTURE? */
1316 if (flags
& VM_LOCKED
) {
1317 locked
= len
>> PAGE_SHIFT
;
1318 locked
+= mm
->locked_vm
;
1319 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
1320 lock_limit
>>= PAGE_SHIFT
;
1321 if (locked
> lock_limit
&& !capable(CAP_IPC_LOCK
))
1328 * The caller must hold down_write(¤t->mm->mmap_sem).
1330 unsigned long do_mmap(struct file
*file
, unsigned long addr
,
1331 unsigned long len
, unsigned long prot
,
1332 unsigned long flags
, vm_flags_t vm_flags
,
1333 unsigned long pgoff
, unsigned long *populate
,
1334 struct list_head
*uf
)
1336 struct mm_struct
*mm
= current
->mm
;
1345 * Does the application expect PROT_READ to imply PROT_EXEC?
1347 * (the exception is when the underlying filesystem is noexec
1348 * mounted, in which case we dont add PROT_EXEC.)
1350 if ((prot
& PROT_READ
) && (current
->personality
& READ_IMPLIES_EXEC
))
1351 if (!(file
&& path_noexec(&file
->f_path
)))
1354 /* force arch specific MAP_FIXED handling in get_unmapped_area */
1355 if (flags
& MAP_FIXED_NOREPLACE
)
1358 if (!(flags
& MAP_FIXED
))
1359 addr
= round_hint_to_min(addr
);
1361 /* Careful about overflows.. */
1362 len
= PAGE_ALIGN(len
);
1366 /* offset overflow? */
1367 if ((pgoff
+ (len
>> PAGE_SHIFT
)) < pgoff
)
1370 /* Too many mappings? */
1371 if (mm
->map_count
> sysctl_max_map_count
)
1374 /* Obtain the address to map to. we verify (or select) it and ensure
1375 * that it represents a valid section of the address space.
1377 addr
= get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
1378 if (offset_in_page(addr
))
1381 if (flags
& MAP_FIXED_NOREPLACE
) {
1382 struct vm_area_struct
*vma
= find_vma(mm
, addr
);
1384 if (vma
&& vma
->vm_start
<= addr
)
1388 if (prot
== PROT_EXEC
) {
1389 pkey
= execute_only_pkey(mm
);
1394 /* Do simple checking here so the lower-level routines won't have
1395 * to. we assume access permissions have been handled by the open
1396 * of the memory object, so we don't do any here.
1398 vm_flags
|= calc_vm_prot_bits(prot
, pkey
) | calc_vm_flag_bits(flags
) |
1399 mm
->def_flags
| VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
;
1401 if (flags
& MAP_LOCKED
)
1402 if (!can_do_mlock())
1405 if (mlock_future_check(mm
, vm_flags
, len
))
1409 struct inode
*inode
= file_inode(file
);
1410 unsigned long flags_mask
;
1412 flags_mask
= LEGACY_MAP_MASK
| file
->f_op
->mmap_supported_flags
;
1414 switch (flags
& MAP_TYPE
) {
1417 * Force use of MAP_SHARED_VALIDATE with non-legacy
1418 * flags. E.g. MAP_SYNC is dangerous to use with
1419 * MAP_SHARED as you don't know which consistency model
1420 * you will get. We silently ignore unsupported flags
1421 * with MAP_SHARED to preserve backward compatibility.
1423 flags
&= LEGACY_MAP_MASK
;
1425 case MAP_SHARED_VALIDATE
:
1426 if (flags
& ~flags_mask
)
1428 if ((prot
&PROT_WRITE
) && !(file
->f_mode
&FMODE_WRITE
))
1432 * Make sure we don't allow writing to an append-only
1435 if (IS_APPEND(inode
) && (file
->f_mode
& FMODE_WRITE
))
1439 * Make sure there are no mandatory locks on the file.
1441 if (locks_verify_locked(file
))
1444 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
1445 if (!(file
->f_mode
& FMODE_WRITE
))
1446 vm_flags
&= ~(VM_MAYWRITE
| VM_SHARED
);
1450 if (!(file
->f_mode
& FMODE_READ
))
1452 if (path_noexec(&file
->f_path
)) {
1453 if (vm_flags
& VM_EXEC
)
1455 vm_flags
&= ~VM_MAYEXEC
;
1458 if (!file
->f_op
->mmap
)
1460 if (vm_flags
& (VM_GROWSDOWN
|VM_GROWSUP
))
1468 switch (flags
& MAP_TYPE
) {
1470 if (vm_flags
& (VM_GROWSDOWN
|VM_GROWSUP
))
1476 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
1480 * Set pgoff according to addr for anon_vma.
1482 pgoff
= addr
>> PAGE_SHIFT
;
1490 * Set 'VM_NORESERVE' if we should not account for the
1491 * memory use of this mapping.
1493 if (flags
& MAP_NORESERVE
) {
1494 /* We honor MAP_NORESERVE if allowed to overcommit */
1495 if (sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
1496 vm_flags
|= VM_NORESERVE
;
1498 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1499 if (file
&& is_file_hugepages(file
))
1500 vm_flags
|= VM_NORESERVE
;
1503 addr
= mmap_region(file
, addr
, len
, vm_flags
, pgoff
, uf
);
1504 if (!IS_ERR_VALUE(addr
) &&
1505 ((vm_flags
& VM_LOCKED
) ||
1506 (flags
& (MAP_POPULATE
| MAP_NONBLOCK
)) == MAP_POPULATE
))
1511 unsigned long ksys_mmap_pgoff(unsigned long addr
, unsigned long len
,
1512 unsigned long prot
, unsigned long flags
,
1513 unsigned long fd
, unsigned long pgoff
)
1515 struct file
*file
= NULL
;
1516 unsigned long retval
;
1518 if (!(flags
& MAP_ANONYMOUS
)) {
1519 audit_mmap_fd(fd
, flags
);
1523 if (is_file_hugepages(file
))
1524 len
= ALIGN(len
, huge_page_size(hstate_file(file
)));
1526 if (unlikely(flags
& MAP_HUGETLB
&& !is_file_hugepages(file
)))
1528 } else if (flags
& MAP_HUGETLB
) {
1529 struct user_struct
*user
= NULL
;
1532 hs
= hstate_sizelog((flags
>> MAP_HUGE_SHIFT
) & MAP_HUGE_MASK
);
1536 len
= ALIGN(len
, huge_page_size(hs
));
1538 * VM_NORESERVE is used because the reservations will be
1539 * taken when vm_ops->mmap() is called
1540 * A dummy user value is used because we are not locking
1541 * memory so no accounting is necessary
1543 file
= hugetlb_file_setup(HUGETLB_ANON_FILE
, len
,
1545 &user
, HUGETLB_ANONHUGE_INODE
,
1546 (flags
>> MAP_HUGE_SHIFT
) & MAP_HUGE_MASK
);
1548 return PTR_ERR(file
);
1551 flags
&= ~(MAP_EXECUTABLE
| MAP_DENYWRITE
);
1553 retval
= vm_mmap_pgoff(file
, addr
, len
, prot
, flags
, pgoff
);
1560 SYSCALL_DEFINE6(mmap_pgoff
, unsigned long, addr
, unsigned long, len
,
1561 unsigned long, prot
, unsigned long, flags
,
1562 unsigned long, fd
, unsigned long, pgoff
)
1564 return ksys_mmap_pgoff(addr
, len
, prot
, flags
, fd
, pgoff
);
1567 #ifdef __ARCH_WANT_SYS_OLD_MMAP
1568 struct mmap_arg_struct
{
1572 unsigned long flags
;
1574 unsigned long offset
;
1577 SYSCALL_DEFINE1(old_mmap
, struct mmap_arg_struct __user
*, arg
)
1579 struct mmap_arg_struct a
;
1581 if (copy_from_user(&a
, arg
, sizeof(a
)))
1583 if (offset_in_page(a
.offset
))
1586 return ksys_mmap_pgoff(a
.addr
, a
.len
, a
.prot
, a
.flags
, a
.fd
,
1587 a
.offset
>> PAGE_SHIFT
);
1589 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
1592 * Some shared mappigns will want the pages marked read-only
1593 * to track write events. If so, we'll downgrade vm_page_prot
1594 * to the private version (using protection_map[] without the
1597 int vma_wants_writenotify(struct vm_area_struct
*vma
, pgprot_t vm_page_prot
)
1599 vm_flags_t vm_flags
= vma
->vm_flags
;
1600 const struct vm_operations_struct
*vm_ops
= vma
->vm_ops
;
1602 /* If it was private or non-writable, the write bit is already clear */
1603 if ((vm_flags
& (VM_WRITE
|VM_SHARED
)) != ((VM_WRITE
|VM_SHARED
)))
1606 /* The backer wishes to know when pages are first written to? */
1607 if (vm_ops
&& (vm_ops
->page_mkwrite
|| vm_ops
->pfn_mkwrite
))
1610 /* The open routine did something to the protections that pgprot_modify
1611 * won't preserve? */
1612 if (pgprot_val(vm_page_prot
) !=
1613 pgprot_val(vm_pgprot_modify(vm_page_prot
, vm_flags
)))
1616 /* Do we need to track softdirty? */
1617 if (IS_ENABLED(CONFIG_MEM_SOFT_DIRTY
) && !(vm_flags
& VM_SOFTDIRTY
))
1620 /* Specialty mapping? */
1621 if (vm_flags
& VM_PFNMAP
)
1624 /* Can the mapping track the dirty pages? */
1625 return vma
->vm_file
&& vma
->vm_file
->f_mapping
&&
1626 mapping_cap_account_dirty(vma
->vm_file
->f_mapping
);
1630 * We account for memory if it's a private writeable mapping,
1631 * not hugepages and VM_NORESERVE wasn't set.
1633 static inline int accountable_mapping(struct file
*file
, vm_flags_t vm_flags
)
1636 * hugetlb has its own accounting separate from the core VM
1637 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1639 if (file
&& is_file_hugepages(file
))
1642 return (vm_flags
& (VM_NORESERVE
| VM_SHARED
| VM_WRITE
)) == VM_WRITE
;
1645 unsigned long mmap_region(struct file
*file
, unsigned long addr
,
1646 unsigned long len
, vm_flags_t vm_flags
, unsigned long pgoff
,
1647 struct list_head
*uf
)
1649 struct mm_struct
*mm
= current
->mm
;
1650 struct vm_area_struct
*vma
, *prev
;
1652 struct rb_node
**rb_link
, *rb_parent
;
1653 unsigned long charged
= 0;
1655 /* Check against address space limit. */
1656 if (!may_expand_vm(mm
, vm_flags
, len
>> PAGE_SHIFT
)) {
1657 unsigned long nr_pages
;
1660 * MAP_FIXED may remove pages of mappings that intersects with
1661 * requested mapping. Account for the pages it would unmap.
1663 nr_pages
= count_vma_pages_range(mm
, addr
, addr
+ len
);
1665 if (!may_expand_vm(mm
, vm_flags
,
1666 (len
>> PAGE_SHIFT
) - nr_pages
))
1670 /* Clear old maps */
1671 while (find_vma_links(mm
, addr
, addr
+ len
, &prev
, &rb_link
,
1673 if (do_munmap(mm
, addr
, len
, uf
))
1678 * Private writable mapping: check memory availability
1680 if (accountable_mapping(file
, vm_flags
)) {
1681 charged
= len
>> PAGE_SHIFT
;
1682 if (security_vm_enough_memory_mm(mm
, charged
))
1684 vm_flags
|= VM_ACCOUNT
;
1688 * Can we just expand an old mapping?
1690 vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, vm_flags
,
1691 NULL
, file
, pgoff
, NULL
, NULL_VM_UFFD_CTX
);
1696 * Determine the object being mapped and call the appropriate
1697 * specific mapper. the address has already been validated, but
1698 * not unmapped, but the maps are removed from the list.
1700 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
1707 vma
->vm_start
= addr
;
1708 vma
->vm_end
= addr
+ len
;
1709 vma
->vm_flags
= vm_flags
;
1710 vma
->vm_page_prot
= vm_get_page_prot(vm_flags
);
1711 vma
->vm_pgoff
= pgoff
;
1712 INIT_LIST_HEAD(&vma
->anon_vma_chain
);
1715 if (vm_flags
& VM_DENYWRITE
) {
1716 error
= deny_write_access(file
);
1720 if (vm_flags
& VM_SHARED
) {
1721 error
= mapping_map_writable(file
->f_mapping
);
1723 goto allow_write_and_free_vma
;
1726 /* ->mmap() can change vma->vm_file, but must guarantee that
1727 * vma_link() below can deny write-access if VM_DENYWRITE is set
1728 * and map writably if VM_SHARED is set. This usually means the
1729 * new file must not have been exposed to user-space, yet.
1731 vma
->vm_file
= get_file(file
);
1732 error
= call_mmap(file
, vma
);
1734 goto unmap_and_free_vma
;
1736 /* Can addr have changed??
1738 * Answer: Yes, several device drivers can do it in their
1739 * f_op->mmap method. -DaveM
1740 * Bug: If addr is changed, prev, rb_link, rb_parent should
1741 * be updated for vma_link()
1743 WARN_ON_ONCE(addr
!= vma
->vm_start
);
1745 addr
= vma
->vm_start
;
1746 vm_flags
= vma
->vm_flags
;
1747 } else if (vm_flags
& VM_SHARED
) {
1748 error
= shmem_zero_setup(vma
);
1753 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
1754 /* Once vma denies write, undo our temporary denial count */
1756 if (vm_flags
& VM_SHARED
)
1757 mapping_unmap_writable(file
->f_mapping
);
1758 if (vm_flags
& VM_DENYWRITE
)
1759 allow_write_access(file
);
1761 file
= vma
->vm_file
;
1763 perf_event_mmap(vma
);
1765 vm_stat_account(mm
, vm_flags
, len
>> PAGE_SHIFT
);
1766 if (vm_flags
& VM_LOCKED
) {
1767 if (!((vm_flags
& VM_SPECIAL
) || is_vm_hugetlb_page(vma
) ||
1768 vma
== get_gate_vma(current
->mm
)))
1769 mm
->locked_vm
+= (len
>> PAGE_SHIFT
);
1771 vma
->vm_flags
&= VM_LOCKED_CLEAR_MASK
;
1778 * New (or expanded) vma always get soft dirty status.
1779 * Otherwise user-space soft-dirty page tracker won't
1780 * be able to distinguish situation when vma area unmapped,
1781 * then new mapped in-place (which must be aimed as
1782 * a completely new data area).
1784 vma
->vm_flags
|= VM_SOFTDIRTY
;
1786 vma_set_page_prot(vma
);
1791 vma
->vm_file
= NULL
;
1794 /* Undo any partial mapping done by a device driver. */
1795 unmap_region(mm
, vma
, prev
, vma
->vm_start
, vma
->vm_end
);
1797 if (vm_flags
& VM_SHARED
)
1798 mapping_unmap_writable(file
->f_mapping
);
1799 allow_write_and_free_vma
:
1800 if (vm_flags
& VM_DENYWRITE
)
1801 allow_write_access(file
);
1803 kmem_cache_free(vm_area_cachep
, vma
);
1806 vm_unacct_memory(charged
);
1810 unsigned long unmapped_area(struct vm_unmapped_area_info
*info
)
1813 * We implement the search by looking for an rbtree node that
1814 * immediately follows a suitable gap. That is,
1815 * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
1816 * - gap_end = vma->vm_start >= info->low_limit + length;
1817 * - gap_end - gap_start >= length
1820 struct mm_struct
*mm
= current
->mm
;
1821 struct vm_area_struct
*vma
;
1822 unsigned long length
, low_limit
, high_limit
, gap_start
, gap_end
;
1824 /* Adjust search length to account for worst case alignment overhead */
1825 length
= info
->length
+ info
->align_mask
;
1826 if (length
< info
->length
)
1829 /* Adjust search limits by the desired length */
1830 if (info
->high_limit
< length
)
1832 high_limit
= info
->high_limit
- length
;
1834 if (info
->low_limit
> high_limit
)
1836 low_limit
= info
->low_limit
+ length
;
1838 /* Check if rbtree root looks promising */
1839 if (RB_EMPTY_ROOT(&mm
->mm_rb
))
1841 vma
= rb_entry(mm
->mm_rb
.rb_node
, struct vm_area_struct
, vm_rb
);
1842 if (vma
->rb_subtree_gap
< length
)
1846 /* Visit left subtree if it looks promising */
1847 gap_end
= vm_start_gap(vma
);
1848 if (gap_end
>= low_limit
&& vma
->vm_rb
.rb_left
) {
1849 struct vm_area_struct
*left
=
1850 rb_entry(vma
->vm_rb
.rb_left
,
1851 struct vm_area_struct
, vm_rb
);
1852 if (left
->rb_subtree_gap
>= length
) {
1858 gap_start
= vma
->vm_prev
? vm_end_gap(vma
->vm_prev
) : 0;
1860 /* Check if current node has a suitable gap */
1861 if (gap_start
> high_limit
)
1863 if (gap_end
>= low_limit
&&
1864 gap_end
> gap_start
&& gap_end
- gap_start
>= length
)
1867 /* Visit right subtree if it looks promising */
1868 if (vma
->vm_rb
.rb_right
) {
1869 struct vm_area_struct
*right
=
1870 rb_entry(vma
->vm_rb
.rb_right
,
1871 struct vm_area_struct
, vm_rb
);
1872 if (right
->rb_subtree_gap
>= length
) {
1878 /* Go back up the rbtree to find next candidate node */
1880 struct rb_node
*prev
= &vma
->vm_rb
;
1881 if (!rb_parent(prev
))
1883 vma
= rb_entry(rb_parent(prev
),
1884 struct vm_area_struct
, vm_rb
);
1885 if (prev
== vma
->vm_rb
.rb_left
) {
1886 gap_start
= vm_end_gap(vma
->vm_prev
);
1887 gap_end
= vm_start_gap(vma
);
1894 /* Check highest gap, which does not precede any rbtree node */
1895 gap_start
= mm
->highest_vm_end
;
1896 gap_end
= ULONG_MAX
; /* Only for VM_BUG_ON below */
1897 if (gap_start
> high_limit
)
1901 /* We found a suitable gap. Clip it with the original low_limit. */
1902 if (gap_start
< info
->low_limit
)
1903 gap_start
= info
->low_limit
;
1905 /* Adjust gap address to the desired alignment */
1906 gap_start
+= (info
->align_offset
- gap_start
) & info
->align_mask
;
1908 VM_BUG_ON(gap_start
+ info
->length
> info
->high_limit
);
1909 VM_BUG_ON(gap_start
+ info
->length
> gap_end
);
1913 unsigned long unmapped_area_topdown(struct vm_unmapped_area_info
*info
)
1915 struct mm_struct
*mm
= current
->mm
;
1916 struct vm_area_struct
*vma
;
1917 unsigned long length
, low_limit
, high_limit
, gap_start
, gap_end
;
1919 /* Adjust search length to account for worst case alignment overhead */
1920 length
= info
->length
+ info
->align_mask
;
1921 if (length
< info
->length
)
1925 * Adjust search limits by the desired length.
1926 * See implementation comment at top of unmapped_area().
1928 gap_end
= info
->high_limit
;
1929 if (gap_end
< length
)
1931 high_limit
= gap_end
- length
;
1933 if (info
->low_limit
> high_limit
)
1935 low_limit
= info
->low_limit
+ length
;
1937 /* Check highest gap, which does not precede any rbtree node */
1938 gap_start
= mm
->highest_vm_end
;
1939 if (gap_start
<= high_limit
)
1942 /* Check if rbtree root looks promising */
1943 if (RB_EMPTY_ROOT(&mm
->mm_rb
))
1945 vma
= rb_entry(mm
->mm_rb
.rb_node
, struct vm_area_struct
, vm_rb
);
1946 if (vma
->rb_subtree_gap
< length
)
1950 /* Visit right subtree if it looks promising */
1951 gap_start
= vma
->vm_prev
? vm_end_gap(vma
->vm_prev
) : 0;
1952 if (gap_start
<= high_limit
&& vma
->vm_rb
.rb_right
) {
1953 struct vm_area_struct
*right
=
1954 rb_entry(vma
->vm_rb
.rb_right
,
1955 struct vm_area_struct
, vm_rb
);
1956 if (right
->rb_subtree_gap
>= length
) {
1963 /* Check if current node has a suitable gap */
1964 gap_end
= vm_start_gap(vma
);
1965 if (gap_end
< low_limit
)
1967 if (gap_start
<= high_limit
&&
1968 gap_end
> gap_start
&& gap_end
- gap_start
>= length
)
1971 /* Visit left subtree if it looks promising */
1972 if (vma
->vm_rb
.rb_left
) {
1973 struct vm_area_struct
*left
=
1974 rb_entry(vma
->vm_rb
.rb_left
,
1975 struct vm_area_struct
, vm_rb
);
1976 if (left
->rb_subtree_gap
>= length
) {
1982 /* Go back up the rbtree to find next candidate node */
1984 struct rb_node
*prev
= &vma
->vm_rb
;
1985 if (!rb_parent(prev
))
1987 vma
= rb_entry(rb_parent(prev
),
1988 struct vm_area_struct
, vm_rb
);
1989 if (prev
== vma
->vm_rb
.rb_right
) {
1990 gap_start
= vma
->vm_prev
?
1991 vm_end_gap(vma
->vm_prev
) : 0;
1998 /* We found a suitable gap. Clip it with the original high_limit. */
1999 if (gap_end
> info
->high_limit
)
2000 gap_end
= info
->high_limit
;
2003 /* Compute highest gap address at the desired alignment */
2004 gap_end
-= info
->length
;
2005 gap_end
-= (gap_end
- info
->align_offset
) & info
->align_mask
;
2007 VM_BUG_ON(gap_end
< info
->low_limit
);
2008 VM_BUG_ON(gap_end
< gap_start
);
2012 /* Get an address range which is currently unmapped.
2013 * For shmat() with addr=0.
2015 * Ugly calling convention alert:
2016 * Return value with the low bits set means error value,
2018 * if (ret & ~PAGE_MASK)
2021 * This function "knows" that -ENOMEM has the bits set.
2023 #ifndef HAVE_ARCH_UNMAPPED_AREA
2025 arch_get_unmapped_area(struct file
*filp
, unsigned long addr
,
2026 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
2028 struct mm_struct
*mm
= current
->mm
;
2029 struct vm_area_struct
*vma
, *prev
;
2030 struct vm_unmapped_area_info info
;
2032 if (len
> TASK_SIZE
- mmap_min_addr
)
2035 if (flags
& MAP_FIXED
)
2039 addr
= PAGE_ALIGN(addr
);
2040 vma
= find_vma_prev(mm
, addr
, &prev
);
2041 if (TASK_SIZE
- len
>= addr
&& addr
>= mmap_min_addr
&&
2042 (!vma
|| addr
+ len
<= vm_start_gap(vma
)) &&
2043 (!prev
|| addr
>= vm_end_gap(prev
)))
2049 info
.low_limit
= mm
->mmap_base
;
2050 info
.high_limit
= TASK_SIZE
;
2051 info
.align_mask
= 0;
2052 return vm_unmapped_area(&info
);
2057 * This mmap-allocator allocates new areas top-down from below the
2058 * stack's low limit (the base):
2060 #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
2062 arch_get_unmapped_area_topdown(struct file
*filp
, const unsigned long addr0
,
2063 const unsigned long len
, const unsigned long pgoff
,
2064 const unsigned long flags
)
2066 struct vm_area_struct
*vma
, *prev
;
2067 struct mm_struct
*mm
= current
->mm
;
2068 unsigned long addr
= addr0
;
2069 struct vm_unmapped_area_info info
;
2071 /* requested length too big for entire address space */
2072 if (len
> TASK_SIZE
- mmap_min_addr
)
2075 if (flags
& MAP_FIXED
)
2078 /* requesting a specific address */
2080 addr
= PAGE_ALIGN(addr
);
2081 vma
= find_vma_prev(mm
, addr
, &prev
);
2082 if (TASK_SIZE
- len
>= addr
&& addr
>= mmap_min_addr
&&
2083 (!vma
|| addr
+ len
<= vm_start_gap(vma
)) &&
2084 (!prev
|| addr
>= vm_end_gap(prev
)))
2088 info
.flags
= VM_UNMAPPED_AREA_TOPDOWN
;
2090 info
.low_limit
= max(PAGE_SIZE
, mmap_min_addr
);
2091 info
.high_limit
= mm
->mmap_base
;
2092 info
.align_mask
= 0;
2093 addr
= vm_unmapped_area(&info
);
2096 * A failed mmap() very likely causes application failure,
2097 * so fall back to the bottom-up function here. This scenario
2098 * can happen with large stack limits and large mmap()
2101 if (offset_in_page(addr
)) {
2102 VM_BUG_ON(addr
!= -ENOMEM
);
2104 info
.low_limit
= TASK_UNMAPPED_BASE
;
2105 info
.high_limit
= TASK_SIZE
;
2106 addr
= vm_unmapped_area(&info
);
2114 get_unmapped_area(struct file
*file
, unsigned long addr
, unsigned long len
,
2115 unsigned long pgoff
, unsigned long flags
)
2117 unsigned long (*get_area
)(struct file
*, unsigned long,
2118 unsigned long, unsigned long, unsigned long);
2120 unsigned long error
= arch_mmap_check(addr
, len
, flags
);
2124 /* Careful about overflows.. */
2125 if (len
> TASK_SIZE
)
2128 get_area
= current
->mm
->get_unmapped_area
;
2130 if (file
->f_op
->get_unmapped_area
)
2131 get_area
= file
->f_op
->get_unmapped_area
;
2132 } else if (flags
& MAP_SHARED
) {
2134 * mmap_region() will call shmem_zero_setup() to create a file,
2135 * so use shmem's get_unmapped_area in case it can be huge.
2136 * do_mmap_pgoff() will clear pgoff, so match alignment.
2139 get_area
= shmem_get_unmapped_area
;
2142 addr
= get_area(file
, addr
, len
, pgoff
, flags
);
2143 if (IS_ERR_VALUE(addr
))
2146 if (addr
> TASK_SIZE
- len
)
2148 if (offset_in_page(addr
))
2151 error
= security_mmap_addr(addr
);
2152 return error
? error
: addr
;
2155 EXPORT_SYMBOL(get_unmapped_area
);
2157 /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
2158 struct vm_area_struct
*find_vma(struct mm_struct
*mm
, unsigned long addr
)
2160 struct rb_node
*rb_node
;
2161 struct vm_area_struct
*vma
;
2163 /* Check the cache first. */
2164 vma
= vmacache_find(mm
, addr
);
2168 rb_node
= mm
->mm_rb
.rb_node
;
2171 struct vm_area_struct
*tmp
;
2173 tmp
= rb_entry(rb_node
, struct vm_area_struct
, vm_rb
);
2175 if (tmp
->vm_end
> addr
) {
2177 if (tmp
->vm_start
<= addr
)
2179 rb_node
= rb_node
->rb_left
;
2181 rb_node
= rb_node
->rb_right
;
2185 vmacache_update(addr
, vma
);
2189 EXPORT_SYMBOL(find_vma
);
2192 * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
2194 struct vm_area_struct
*
2195 find_vma_prev(struct mm_struct
*mm
, unsigned long addr
,
2196 struct vm_area_struct
**pprev
)
2198 struct vm_area_struct
*vma
;
2200 vma
= find_vma(mm
, addr
);
2202 *pprev
= vma
->vm_prev
;
2204 struct rb_node
*rb_node
= mm
->mm_rb
.rb_node
;
2207 *pprev
= rb_entry(rb_node
, struct vm_area_struct
, vm_rb
);
2208 rb_node
= rb_node
->rb_right
;
2215 * Verify that the stack growth is acceptable and
2216 * update accounting. This is shared with both the
2217 * grow-up and grow-down cases.
2219 static int acct_stack_growth(struct vm_area_struct
*vma
,
2220 unsigned long size
, unsigned long grow
)
2222 struct mm_struct
*mm
= vma
->vm_mm
;
2223 unsigned long new_start
;
2225 /* address space limit tests */
2226 if (!may_expand_vm(mm
, vma
->vm_flags
, grow
))
2229 /* Stack limit test */
2230 if (size
> rlimit(RLIMIT_STACK
))
2233 /* mlock limit tests */
2234 if (vma
->vm_flags
& VM_LOCKED
) {
2235 unsigned long locked
;
2236 unsigned long limit
;
2237 locked
= mm
->locked_vm
+ grow
;
2238 limit
= rlimit(RLIMIT_MEMLOCK
);
2239 limit
>>= PAGE_SHIFT
;
2240 if (locked
> limit
&& !capable(CAP_IPC_LOCK
))
2244 /* Check to ensure the stack will not grow into a hugetlb-only region */
2245 new_start
= (vma
->vm_flags
& VM_GROWSUP
) ? vma
->vm_start
:
2247 if (is_hugepage_only_range(vma
->vm_mm
, new_start
, size
))
2251 * Overcommit.. This must be the final test, as it will
2252 * update security statistics.
2254 if (security_vm_enough_memory_mm(mm
, grow
))
2260 #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
2262 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
2263 * vma is the last one with address > vma->vm_end. Have to extend vma.
2265 int expand_upwards(struct vm_area_struct
*vma
, unsigned long address
)
2267 struct mm_struct
*mm
= vma
->vm_mm
;
2268 struct vm_area_struct
*next
;
2269 unsigned long gap_addr
;
2272 if (!(vma
->vm_flags
& VM_GROWSUP
))
2275 /* Guard against exceeding limits of the address space. */
2276 address
&= PAGE_MASK
;
2277 if (address
>= (TASK_SIZE
& PAGE_MASK
))
2279 address
+= PAGE_SIZE
;
2281 /* Enforce stack_guard_gap */
2282 gap_addr
= address
+ stack_guard_gap
;
2284 /* Guard against overflow */
2285 if (gap_addr
< address
|| gap_addr
> TASK_SIZE
)
2286 gap_addr
= TASK_SIZE
;
2288 next
= vma
->vm_next
;
2289 if (next
&& next
->vm_start
< gap_addr
&&
2290 (next
->vm_flags
& (VM_WRITE
|VM_READ
|VM_EXEC
))) {
2291 if (!(next
->vm_flags
& VM_GROWSUP
))
2293 /* Check that both stack segments have the same anon_vma? */
2296 /* We must make sure the anon_vma is allocated. */
2297 if (unlikely(anon_vma_prepare(vma
)))
2301 * vma->vm_start/vm_end cannot change under us because the caller
2302 * is required to hold the mmap_sem in read mode. We need the
2303 * anon_vma lock to serialize against concurrent expand_stacks.
2305 anon_vma_lock_write(vma
->anon_vma
);
2307 /* Somebody else might have raced and expanded it already */
2308 if (address
> vma
->vm_end
) {
2309 unsigned long size
, grow
;
2311 size
= address
- vma
->vm_start
;
2312 grow
= (address
- vma
->vm_end
) >> PAGE_SHIFT
;
2315 if (vma
->vm_pgoff
+ (size
>> PAGE_SHIFT
) >= vma
->vm_pgoff
) {
2316 error
= acct_stack_growth(vma
, size
, grow
);
2319 * vma_gap_update() doesn't support concurrent
2320 * updates, but we only hold a shared mmap_sem
2321 * lock here, so we need to protect against
2322 * concurrent vma expansions.
2323 * anon_vma_lock_write() doesn't help here, as
2324 * we don't guarantee that all growable vmas
2325 * in a mm share the same root anon vma.
2326 * So, we reuse mm->page_table_lock to guard
2327 * against concurrent vma expansions.
2329 spin_lock(&mm
->page_table_lock
);
2330 if (vma
->vm_flags
& VM_LOCKED
)
2331 mm
->locked_vm
+= grow
;
2332 vm_stat_account(mm
, vma
->vm_flags
, grow
);
2333 anon_vma_interval_tree_pre_update_vma(vma
);
2334 vma
->vm_end
= address
;
2335 anon_vma_interval_tree_post_update_vma(vma
);
2337 vma_gap_update(vma
->vm_next
);
2339 mm
->highest_vm_end
= vm_end_gap(vma
);
2340 spin_unlock(&mm
->page_table_lock
);
2342 perf_event_mmap(vma
);
2346 anon_vma_unlock_write(vma
->anon_vma
);
2347 khugepaged_enter_vma_merge(vma
, vma
->vm_flags
);
2351 #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
2354 * vma is the first one with address < vma->vm_start. Have to extend vma.
2356 int expand_downwards(struct vm_area_struct
*vma
,
2357 unsigned long address
)
2359 struct mm_struct
*mm
= vma
->vm_mm
;
2360 struct vm_area_struct
*prev
;
2363 address
&= PAGE_MASK
;
2364 error
= security_mmap_addr(address
);
2368 /* Enforce stack_guard_gap */
2369 prev
= vma
->vm_prev
;
2370 /* Check that both stack segments have the same anon_vma? */
2371 if (prev
&& !(prev
->vm_flags
& VM_GROWSDOWN
) &&
2372 (prev
->vm_flags
& (VM_WRITE
|VM_READ
|VM_EXEC
))) {
2373 if (address
- prev
->vm_end
< stack_guard_gap
)
2377 /* We must make sure the anon_vma is allocated. */
2378 if (unlikely(anon_vma_prepare(vma
)))
2382 * vma->vm_start/vm_end cannot change under us because the caller
2383 * is required to hold the mmap_sem in read mode. We need the
2384 * anon_vma lock to serialize against concurrent expand_stacks.
2386 anon_vma_lock_write(vma
->anon_vma
);
2388 /* Somebody else might have raced and expanded it already */
2389 if (address
< vma
->vm_start
) {
2390 unsigned long size
, grow
;
2392 size
= vma
->vm_end
- address
;
2393 grow
= (vma
->vm_start
- address
) >> PAGE_SHIFT
;
2396 if (grow
<= vma
->vm_pgoff
) {
2397 error
= acct_stack_growth(vma
, size
, grow
);
2400 * vma_gap_update() doesn't support concurrent
2401 * updates, but we only hold a shared mmap_sem
2402 * lock here, so we need to protect against
2403 * concurrent vma expansions.
2404 * anon_vma_lock_write() doesn't help here, as
2405 * we don't guarantee that all growable vmas
2406 * in a mm share the same root anon vma.
2407 * So, we reuse mm->page_table_lock to guard
2408 * against concurrent vma expansions.
2410 spin_lock(&mm
->page_table_lock
);
2411 if (vma
->vm_flags
& VM_LOCKED
)
2412 mm
->locked_vm
+= grow
;
2413 vm_stat_account(mm
, vma
->vm_flags
, grow
);
2414 anon_vma_interval_tree_pre_update_vma(vma
);
2415 vma
->vm_start
= address
;
2416 vma
->vm_pgoff
-= grow
;
2417 anon_vma_interval_tree_post_update_vma(vma
);
2418 vma_gap_update(vma
);
2419 spin_unlock(&mm
->page_table_lock
);
2421 perf_event_mmap(vma
);
2425 anon_vma_unlock_write(vma
->anon_vma
);
2426 khugepaged_enter_vma_merge(vma
, vma
->vm_flags
);
2431 /* enforced gap between the expanding stack and other mappings. */
2432 unsigned long stack_guard_gap
= 256UL<<PAGE_SHIFT
;
2434 static int __init
cmdline_parse_stack_guard_gap(char *p
)
2439 val
= simple_strtoul(p
, &endptr
, 10);
2441 stack_guard_gap
= val
<< PAGE_SHIFT
;
2445 __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap
);
2447 #ifdef CONFIG_STACK_GROWSUP
2448 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
2450 return expand_upwards(vma
, address
);
2453 struct vm_area_struct
*
2454 find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
2456 struct vm_area_struct
*vma
, *prev
;
2459 vma
= find_vma_prev(mm
, addr
, &prev
);
2460 if (vma
&& (vma
->vm_start
<= addr
))
2462 if (!prev
|| expand_stack(prev
, addr
))
2464 if (prev
->vm_flags
& VM_LOCKED
)
2465 populate_vma_page_range(prev
, addr
, prev
->vm_end
, NULL
);
2469 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
2471 return expand_downwards(vma
, address
);
2474 struct vm_area_struct
*
2475 find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
2477 struct vm_area_struct
*vma
;
2478 unsigned long start
;
2481 vma
= find_vma(mm
, addr
);
2484 if (vma
->vm_start
<= addr
)
2486 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
2488 start
= vma
->vm_start
;
2489 if (expand_stack(vma
, addr
))
2491 if (vma
->vm_flags
& VM_LOCKED
)
2492 populate_vma_page_range(vma
, addr
, start
, NULL
);
2497 EXPORT_SYMBOL_GPL(find_extend_vma
);
2500 * Ok - we have the memory areas we should free on the vma list,
2501 * so release them, and do the vma updates.
2503 * Called with the mm semaphore held.
2505 static void remove_vma_list(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
2507 unsigned long nr_accounted
= 0;
2509 /* Update high watermark before we lower total_vm */
2510 update_hiwater_vm(mm
);
2512 long nrpages
= vma_pages(vma
);
2514 if (vma
->vm_flags
& VM_ACCOUNT
)
2515 nr_accounted
+= nrpages
;
2516 vm_stat_account(mm
, vma
->vm_flags
, -nrpages
);
2517 vma
= remove_vma(vma
);
2519 vm_unacct_memory(nr_accounted
);
2524 * Get rid of page table information in the indicated region.
2526 * Called with the mm semaphore held.
2528 static void unmap_region(struct mm_struct
*mm
,
2529 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
2530 unsigned long start
, unsigned long end
)
2532 struct vm_area_struct
*next
= prev
? prev
->vm_next
: mm
->mmap
;
2533 struct mmu_gather tlb
;
2536 tlb_gather_mmu(&tlb
, mm
, start
, end
);
2537 update_hiwater_rss(mm
);
2538 unmap_vmas(&tlb
, vma
, start
, end
);
2539 free_pgtables(&tlb
, vma
, prev
? prev
->vm_end
: FIRST_USER_ADDRESS
,
2540 next
? next
->vm_start
: USER_PGTABLES_CEILING
);
2541 tlb_finish_mmu(&tlb
, start
, end
);
2545 * Create a list of vma's touched by the unmap, removing them from the mm's
2546 * vma list as we go..
2549 detach_vmas_to_be_unmapped(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2550 struct vm_area_struct
*prev
, unsigned long end
)
2552 struct vm_area_struct
**insertion_point
;
2553 struct vm_area_struct
*tail_vma
= NULL
;
2555 insertion_point
= (prev
? &prev
->vm_next
: &mm
->mmap
);
2556 vma
->vm_prev
= NULL
;
2558 vma_rb_erase(vma
, &mm
->mm_rb
);
2562 } while (vma
&& vma
->vm_start
< end
);
2563 *insertion_point
= vma
;
2565 vma
->vm_prev
= prev
;
2566 vma_gap_update(vma
);
2568 mm
->highest_vm_end
= prev
? vm_end_gap(prev
) : 0;
2569 tail_vma
->vm_next
= NULL
;
2571 /* Kill the cache */
2572 vmacache_invalidate(mm
);
2576 * __split_vma() bypasses sysctl_max_map_count checking. We use this where it
2577 * has already been checked or doesn't make sense to fail.
2579 int __split_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2580 unsigned long addr
, int new_below
)
2582 struct vm_area_struct
*new;
2585 if (vma
->vm_ops
&& vma
->vm_ops
->split
) {
2586 err
= vma
->vm_ops
->split(vma
, addr
);
2591 new = kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
2595 /* most fields are the same, copy all, and then fixup */
2598 INIT_LIST_HEAD(&new->anon_vma_chain
);
2603 new->vm_start
= addr
;
2604 new->vm_pgoff
+= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
);
2607 err
= vma_dup_policy(vma
, new);
2611 err
= anon_vma_clone(new, vma
);
2616 get_file(new->vm_file
);
2618 if (new->vm_ops
&& new->vm_ops
->open
)
2619 new->vm_ops
->open(new);
2622 err
= vma_adjust(vma
, addr
, vma
->vm_end
, vma
->vm_pgoff
+
2623 ((addr
- new->vm_start
) >> PAGE_SHIFT
), new);
2625 err
= vma_adjust(vma
, vma
->vm_start
, addr
, vma
->vm_pgoff
, new);
2631 /* Clean everything up if vma_adjust failed. */
2632 if (new->vm_ops
&& new->vm_ops
->close
)
2633 new->vm_ops
->close(new);
2636 unlink_anon_vmas(new);
2638 mpol_put(vma_policy(new));
2640 kmem_cache_free(vm_area_cachep
, new);
2645 * Split a vma into two pieces at address 'addr', a new vma is allocated
2646 * either for the first part or the tail.
2648 int split_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2649 unsigned long addr
, int new_below
)
2651 if (mm
->map_count
>= sysctl_max_map_count
)
2654 return __split_vma(mm
, vma
, addr
, new_below
);
2657 /* Munmap is split into 2 main parts -- this part which finds
2658 * what needs doing, and the areas themselves, which do the
2659 * work. This now handles partial unmappings.
2660 * Jeremy Fitzhardinge <jeremy@goop.org>
2662 int do_munmap(struct mm_struct
*mm
, unsigned long start
, size_t len
,
2663 struct list_head
*uf
)
2666 struct vm_area_struct
*vma
, *prev
, *last
;
2668 if ((offset_in_page(start
)) || start
> TASK_SIZE
|| len
> TASK_SIZE
-start
)
2671 len
= PAGE_ALIGN(len
);
2675 /* Find the first overlapping VMA */
2676 vma
= find_vma(mm
, start
);
2679 prev
= vma
->vm_prev
;
2680 /* we have start < vma->vm_end */
2682 /* if it doesn't overlap, we have nothing.. */
2684 if (vma
->vm_start
>= end
)
2688 * If we need to split any vma, do it now to save pain later.
2690 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2691 * unmapped vm_area_struct will remain in use: so lower split_vma
2692 * places tmp vma above, and higher split_vma places tmp vma below.
2694 if (start
> vma
->vm_start
) {
2698 * Make sure that map_count on return from munmap() will
2699 * not exceed its limit; but let map_count go just above
2700 * its limit temporarily, to help free resources as expected.
2702 if (end
< vma
->vm_end
&& mm
->map_count
>= sysctl_max_map_count
)
2705 error
= __split_vma(mm
, vma
, start
, 0);
2711 /* Does it split the last one? */
2712 last
= find_vma(mm
, end
);
2713 if (last
&& end
> last
->vm_start
) {
2714 int error
= __split_vma(mm
, last
, end
, 1);
2718 vma
= prev
? prev
->vm_next
: mm
->mmap
;
2722 * If userfaultfd_unmap_prep returns an error the vmas
2723 * will remain splitted, but userland will get a
2724 * highly unexpected error anyway. This is no
2725 * different than the case where the first of the two
2726 * __split_vma fails, but we don't undo the first
2727 * split, despite we could. This is unlikely enough
2728 * failure that it's not worth optimizing it for.
2730 int error
= userfaultfd_unmap_prep(vma
, start
, end
, uf
);
2736 * unlock any mlock()ed ranges before detaching vmas
2738 if (mm
->locked_vm
) {
2739 struct vm_area_struct
*tmp
= vma
;
2740 while (tmp
&& tmp
->vm_start
< end
) {
2741 if (tmp
->vm_flags
& VM_LOCKED
) {
2742 mm
->locked_vm
-= vma_pages(tmp
);
2743 munlock_vma_pages_all(tmp
);
2750 * Remove the vma's, and unmap the actual pages
2752 detach_vmas_to_be_unmapped(mm
, vma
, prev
, end
);
2753 unmap_region(mm
, vma
, prev
, start
, end
);
2755 arch_unmap(mm
, vma
, start
, end
);
2757 /* Fix up all other VM information */
2758 remove_vma_list(mm
, vma
);
2763 int vm_munmap(unsigned long start
, size_t len
)
2766 struct mm_struct
*mm
= current
->mm
;
2769 if (down_write_killable(&mm
->mmap_sem
))
2772 ret
= do_munmap(mm
, start
, len
, &uf
);
2773 up_write(&mm
->mmap_sem
);
2774 userfaultfd_unmap_complete(mm
, &uf
);
2777 EXPORT_SYMBOL(vm_munmap
);
2779 SYSCALL_DEFINE2(munmap
, unsigned long, addr
, size_t, len
)
2781 profile_munmap(addr
);
2782 return vm_munmap(addr
, len
);
2787 * Emulation of deprecated remap_file_pages() syscall.
2789 SYSCALL_DEFINE5(remap_file_pages
, unsigned long, start
, unsigned long, size
,
2790 unsigned long, prot
, unsigned long, pgoff
, unsigned long, flags
)
2793 struct mm_struct
*mm
= current
->mm
;
2794 struct vm_area_struct
*vma
;
2795 unsigned long populate
= 0;
2796 unsigned long ret
= -EINVAL
;
2799 pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.txt.\n",
2800 current
->comm
, current
->pid
);
2804 start
= start
& PAGE_MASK
;
2805 size
= size
& PAGE_MASK
;
2807 if (start
+ size
<= start
)
2810 /* Does pgoff wrap? */
2811 if (pgoff
+ (size
>> PAGE_SHIFT
) < pgoff
)
2814 if (down_write_killable(&mm
->mmap_sem
))
2817 vma
= find_vma(mm
, start
);
2819 if (!vma
|| !(vma
->vm_flags
& VM_SHARED
))
2822 if (start
< vma
->vm_start
)
2825 if (start
+ size
> vma
->vm_end
) {
2826 struct vm_area_struct
*next
;
2828 for (next
= vma
->vm_next
; next
; next
= next
->vm_next
) {
2829 /* hole between vmas ? */
2830 if (next
->vm_start
!= next
->vm_prev
->vm_end
)
2833 if (next
->vm_file
!= vma
->vm_file
)
2836 if (next
->vm_flags
!= vma
->vm_flags
)
2839 if (start
+ size
<= next
->vm_end
)
2847 prot
|= vma
->vm_flags
& VM_READ
? PROT_READ
: 0;
2848 prot
|= vma
->vm_flags
& VM_WRITE
? PROT_WRITE
: 0;
2849 prot
|= vma
->vm_flags
& VM_EXEC
? PROT_EXEC
: 0;
2851 flags
&= MAP_NONBLOCK
;
2852 flags
|= MAP_SHARED
| MAP_FIXED
| MAP_POPULATE
;
2853 if (vma
->vm_flags
& VM_LOCKED
) {
2854 struct vm_area_struct
*tmp
;
2855 flags
|= MAP_LOCKED
;
2857 /* drop PG_Mlocked flag for over-mapped range */
2858 for (tmp
= vma
; tmp
->vm_start
>= start
+ size
;
2859 tmp
= tmp
->vm_next
) {
2861 * Split pmd and munlock page on the border
2864 vma_adjust_trans_huge(tmp
, start
, start
+ size
, 0);
2866 munlock_vma_pages_range(tmp
,
2867 max(tmp
->vm_start
, start
),
2868 min(tmp
->vm_end
, start
+ size
));
2872 file
= get_file(vma
->vm_file
);
2873 ret
= do_mmap_pgoff(vma
->vm_file
, start
, size
,
2874 prot
, flags
, pgoff
, &populate
, NULL
);
2877 up_write(&mm
->mmap_sem
);
2879 mm_populate(ret
, populate
);
2880 if (!IS_ERR_VALUE(ret
))
2885 static inline void verify_mm_writelocked(struct mm_struct
*mm
)
2887 #ifdef CONFIG_DEBUG_VM
2888 if (unlikely(down_read_trylock(&mm
->mmap_sem
))) {
2890 up_read(&mm
->mmap_sem
);
2896 * this is really a simplified "do_mmap". it only handles
2897 * anonymous maps. eventually we may be able to do some
2898 * brk-specific accounting here.
2900 static int do_brk_flags(unsigned long addr
, unsigned long request
, unsigned long flags
, struct list_head
*uf
)
2902 struct mm_struct
*mm
= current
->mm
;
2903 struct vm_area_struct
*vma
, *prev
;
2905 struct rb_node
**rb_link
, *rb_parent
;
2906 pgoff_t pgoff
= addr
>> PAGE_SHIFT
;
2909 len
= PAGE_ALIGN(request
);
2915 /* Until we need other flags, refuse anything except VM_EXEC. */
2916 if ((flags
& (~VM_EXEC
)) != 0)
2918 flags
|= VM_DATA_DEFAULT_FLAGS
| VM_ACCOUNT
| mm
->def_flags
;
2920 error
= get_unmapped_area(NULL
, addr
, len
, 0, MAP_FIXED
);
2921 if (offset_in_page(error
))
2924 error
= mlock_future_check(mm
, mm
->def_flags
, len
);
2929 * mm->mmap_sem is required to protect against another thread
2930 * changing the mappings in case we sleep.
2932 verify_mm_writelocked(mm
);
2935 * Clear old maps. this also does some error checking for us
2937 while (find_vma_links(mm
, addr
, addr
+ len
, &prev
, &rb_link
,
2939 if (do_munmap(mm
, addr
, len
, uf
))
2943 /* Check against address space limits *after* clearing old maps... */
2944 if (!may_expand_vm(mm
, flags
, len
>> PAGE_SHIFT
))
2947 if (mm
->map_count
> sysctl_max_map_count
)
2950 if (security_vm_enough_memory_mm(mm
, len
>> PAGE_SHIFT
))
2953 /* Can we just expand an old private anonymous mapping? */
2954 vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, flags
,
2955 NULL
, NULL
, pgoff
, NULL
, NULL_VM_UFFD_CTX
);
2960 * create a vma struct for an anonymous mapping
2962 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
2964 vm_unacct_memory(len
>> PAGE_SHIFT
);
2968 INIT_LIST_HEAD(&vma
->anon_vma_chain
);
2970 vma
->vm_start
= addr
;
2971 vma
->vm_end
= addr
+ len
;
2972 vma
->vm_pgoff
= pgoff
;
2973 vma
->vm_flags
= flags
;
2974 vma
->vm_page_prot
= vm_get_page_prot(flags
);
2975 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
2977 perf_event_mmap(vma
);
2978 mm
->total_vm
+= len
>> PAGE_SHIFT
;
2979 mm
->data_vm
+= len
>> PAGE_SHIFT
;
2980 if (flags
& VM_LOCKED
)
2981 mm
->locked_vm
+= (len
>> PAGE_SHIFT
);
2982 vma
->vm_flags
|= VM_SOFTDIRTY
;
2986 static int do_brk(unsigned long addr
, unsigned long len
, struct list_head
*uf
)
2988 return do_brk_flags(addr
, len
, 0, uf
);
2991 int vm_brk_flags(unsigned long addr
, unsigned long len
, unsigned long flags
)
2993 struct mm_struct
*mm
= current
->mm
;
2998 if (down_write_killable(&mm
->mmap_sem
))
3001 ret
= do_brk_flags(addr
, len
, flags
, &uf
);
3002 populate
= ((mm
->def_flags
& VM_LOCKED
) != 0);
3003 up_write(&mm
->mmap_sem
);
3004 userfaultfd_unmap_complete(mm
, &uf
);
3005 if (populate
&& !ret
)
3006 mm_populate(addr
, len
);
3009 EXPORT_SYMBOL(vm_brk_flags
);
3011 int vm_brk(unsigned long addr
, unsigned long len
)
3013 return vm_brk_flags(addr
, len
, 0);
3015 EXPORT_SYMBOL(vm_brk
);
3017 /* Release all mmaps. */
3018 void exit_mmap(struct mm_struct
*mm
)
3020 struct mmu_gather tlb
;
3021 struct vm_area_struct
*vma
;
3022 unsigned long nr_accounted
= 0;
3024 /* mm's last user has gone, and its about to be pulled down */
3025 mmu_notifier_release(mm
);
3027 if (mm
->locked_vm
) {
3030 if (vma
->vm_flags
& VM_LOCKED
)
3031 munlock_vma_pages_all(vma
);
3039 if (!vma
) /* Can happen if dup_mmap() received an OOM */
3044 tlb_gather_mmu(&tlb
, mm
, 0, -1);
3045 /* update_hiwater_rss(mm) here? but nobody should be looking */
3046 /* Use -1 here to ensure all VMAs in the mm are unmapped */
3047 unmap_vmas(&tlb
, vma
, 0, -1);
3049 if (unlikely(mm_is_oom_victim(mm
))) {
3051 * Wait for oom_reap_task() to stop working on this
3052 * mm. Because MMF_OOM_SKIP is already set before
3053 * calling down_read(), oom_reap_task() will not run
3054 * on this "mm" post up_write().
3056 * mm_is_oom_victim() cannot be set from under us
3057 * either because victim->mm is already set to NULL
3058 * under task_lock before calling mmput and oom_mm is
3059 * set not NULL by the OOM killer only if victim->mm
3060 * is found not NULL while holding the task_lock.
3062 set_bit(MMF_OOM_SKIP
, &mm
->flags
);
3063 down_write(&mm
->mmap_sem
);
3064 up_write(&mm
->mmap_sem
);
3066 free_pgtables(&tlb
, vma
, FIRST_USER_ADDRESS
, USER_PGTABLES_CEILING
);
3067 tlb_finish_mmu(&tlb
, 0, -1);
3070 * Walk the list again, actually closing and freeing it,
3071 * with preemption enabled, without holding any MM locks.
3074 if (vma
->vm_flags
& VM_ACCOUNT
)
3075 nr_accounted
+= vma_pages(vma
);
3076 vma
= remove_vma(vma
);
3078 vm_unacct_memory(nr_accounted
);
3081 /* Insert vm structure into process list sorted by address
3082 * and into the inode's i_mmap tree. If vm_file is non-NULL
3083 * then i_mmap_rwsem is taken here.
3085 int insert_vm_struct(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
3087 struct vm_area_struct
*prev
;
3088 struct rb_node
**rb_link
, *rb_parent
;
3090 if (find_vma_links(mm
, vma
->vm_start
, vma
->vm_end
,
3091 &prev
, &rb_link
, &rb_parent
))
3093 if ((vma
->vm_flags
& VM_ACCOUNT
) &&
3094 security_vm_enough_memory_mm(mm
, vma_pages(vma
)))
3098 * The vm_pgoff of a purely anonymous vma should be irrelevant
3099 * until its first write fault, when page's anon_vma and index
3100 * are set. But now set the vm_pgoff it will almost certainly
3101 * end up with (unless mremap moves it elsewhere before that
3102 * first wfault), so /proc/pid/maps tells a consistent story.
3104 * By setting it to reflect the virtual start address of the
3105 * vma, merges and splits can happen in a seamless way, just
3106 * using the existing file pgoff checks and manipulations.
3107 * Similarly in do_mmap_pgoff and in do_brk.
3109 if (vma_is_anonymous(vma
)) {
3110 BUG_ON(vma
->anon_vma
);
3111 vma
->vm_pgoff
= vma
->vm_start
>> PAGE_SHIFT
;
3114 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
3119 * Copy the vma structure to a new location in the same mm,
3120 * prior to moving page table entries, to effect an mremap move.
3122 struct vm_area_struct
*copy_vma(struct vm_area_struct
**vmap
,
3123 unsigned long addr
, unsigned long len
, pgoff_t pgoff
,
3124 bool *need_rmap_locks
)
3126 struct vm_area_struct
*vma
= *vmap
;
3127 unsigned long vma_start
= vma
->vm_start
;
3128 struct mm_struct
*mm
= vma
->vm_mm
;
3129 struct vm_area_struct
*new_vma
, *prev
;
3130 struct rb_node
**rb_link
, *rb_parent
;
3131 bool faulted_in_anon_vma
= true;
3134 * If anonymous vma has not yet been faulted, update new pgoff
3135 * to match new location, to increase its chance of merging.
3137 if (unlikely(vma_is_anonymous(vma
) && !vma
->anon_vma
)) {
3138 pgoff
= addr
>> PAGE_SHIFT
;
3139 faulted_in_anon_vma
= false;
3142 if (find_vma_links(mm
, addr
, addr
+ len
, &prev
, &rb_link
, &rb_parent
))
3143 return NULL
; /* should never get here */
3144 new_vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, vma
->vm_flags
,
3145 vma
->anon_vma
, vma
->vm_file
, pgoff
, vma_policy(vma
),
3146 vma
->vm_userfaultfd_ctx
);
3149 * Source vma may have been merged into new_vma
3151 if (unlikely(vma_start
>= new_vma
->vm_start
&&
3152 vma_start
< new_vma
->vm_end
)) {
3154 * The only way we can get a vma_merge with
3155 * self during an mremap is if the vma hasn't
3156 * been faulted in yet and we were allowed to
3157 * reset the dst vma->vm_pgoff to the
3158 * destination address of the mremap to allow
3159 * the merge to happen. mremap must change the
3160 * vm_pgoff linearity between src and dst vmas
3161 * (in turn preventing a vma_merge) to be
3162 * safe. It is only safe to keep the vm_pgoff
3163 * linear if there are no pages mapped yet.
3165 VM_BUG_ON_VMA(faulted_in_anon_vma
, new_vma
);
3166 *vmap
= vma
= new_vma
;
3168 *need_rmap_locks
= (new_vma
->vm_pgoff
<= vma
->vm_pgoff
);
3170 new_vma
= kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
3174 new_vma
->vm_start
= addr
;
3175 new_vma
->vm_end
= addr
+ len
;
3176 new_vma
->vm_pgoff
= pgoff
;
3177 if (vma_dup_policy(vma
, new_vma
))
3179 INIT_LIST_HEAD(&new_vma
->anon_vma_chain
);
3180 if (anon_vma_clone(new_vma
, vma
))
3181 goto out_free_mempol
;
3182 if (new_vma
->vm_file
)
3183 get_file(new_vma
->vm_file
);
3184 if (new_vma
->vm_ops
&& new_vma
->vm_ops
->open
)
3185 new_vma
->vm_ops
->open(new_vma
);
3186 vma_link(mm
, new_vma
, prev
, rb_link
, rb_parent
);
3187 *need_rmap_locks
= false;
3192 mpol_put(vma_policy(new_vma
));
3194 kmem_cache_free(vm_area_cachep
, new_vma
);
3200 * Return true if the calling process may expand its vm space by the passed
3203 bool may_expand_vm(struct mm_struct
*mm
, vm_flags_t flags
, unsigned long npages
)
3205 if (mm
->total_vm
+ npages
> rlimit(RLIMIT_AS
) >> PAGE_SHIFT
)
3208 if (is_data_mapping(flags
) &&
3209 mm
->data_vm
+ npages
> rlimit(RLIMIT_DATA
) >> PAGE_SHIFT
) {
3210 /* Workaround for Valgrind */
3211 if (rlimit(RLIMIT_DATA
) == 0 &&
3212 mm
->data_vm
+ npages
<= rlimit_max(RLIMIT_DATA
) >> PAGE_SHIFT
)
3215 pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
3216 current
->comm
, current
->pid
,
3217 (mm
->data_vm
+ npages
) << PAGE_SHIFT
,
3218 rlimit(RLIMIT_DATA
),
3219 ignore_rlimit_data
? "" : " or use boot option ignore_rlimit_data");
3221 if (!ignore_rlimit_data
)
3228 void vm_stat_account(struct mm_struct
*mm
, vm_flags_t flags
, long npages
)
3230 mm
->total_vm
+= npages
;
3232 if (is_exec_mapping(flags
))
3233 mm
->exec_vm
+= npages
;
3234 else if (is_stack_mapping(flags
))
3235 mm
->stack_vm
+= npages
;
3236 else if (is_data_mapping(flags
))
3237 mm
->data_vm
+= npages
;
3240 static int special_mapping_fault(struct vm_fault
*vmf
);
3243 * Having a close hook prevents vma merging regardless of flags.
3245 static void special_mapping_close(struct vm_area_struct
*vma
)
3249 static const char *special_mapping_name(struct vm_area_struct
*vma
)
3251 return ((struct vm_special_mapping
*)vma
->vm_private_data
)->name
;
3254 static int special_mapping_mremap(struct vm_area_struct
*new_vma
)
3256 struct vm_special_mapping
*sm
= new_vma
->vm_private_data
;
3258 if (WARN_ON_ONCE(current
->mm
!= new_vma
->vm_mm
))
3262 return sm
->mremap(sm
, new_vma
);
3267 static const struct vm_operations_struct special_mapping_vmops
= {
3268 .close
= special_mapping_close
,
3269 .fault
= special_mapping_fault
,
3270 .mremap
= special_mapping_mremap
,
3271 .name
= special_mapping_name
,
3274 static const struct vm_operations_struct legacy_special_mapping_vmops
= {
3275 .close
= special_mapping_close
,
3276 .fault
= special_mapping_fault
,
3279 static int special_mapping_fault(struct vm_fault
*vmf
)
3281 struct vm_area_struct
*vma
= vmf
->vma
;
3283 struct page
**pages
;
3285 if (vma
->vm_ops
== &legacy_special_mapping_vmops
) {
3286 pages
= vma
->vm_private_data
;
3288 struct vm_special_mapping
*sm
= vma
->vm_private_data
;
3291 return sm
->fault(sm
, vmf
->vma
, vmf
);
3296 for (pgoff
= vmf
->pgoff
; pgoff
&& *pages
; ++pages
)
3300 struct page
*page
= *pages
;
3306 return VM_FAULT_SIGBUS
;
3309 static struct vm_area_struct
*__install_special_mapping(
3310 struct mm_struct
*mm
,
3311 unsigned long addr
, unsigned long len
,
3312 unsigned long vm_flags
, void *priv
,
3313 const struct vm_operations_struct
*ops
)
3316 struct vm_area_struct
*vma
;
3318 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
3319 if (unlikely(vma
== NULL
))
3320 return ERR_PTR(-ENOMEM
);
3322 INIT_LIST_HEAD(&vma
->anon_vma_chain
);
3324 vma
->vm_start
= addr
;
3325 vma
->vm_end
= addr
+ len
;
3327 vma
->vm_flags
= vm_flags
| mm
->def_flags
| VM_DONTEXPAND
| VM_SOFTDIRTY
;
3328 vma
->vm_page_prot
= vm_get_page_prot(vma
->vm_flags
);
3331 vma
->vm_private_data
= priv
;
3333 ret
= insert_vm_struct(mm
, vma
);
3337 vm_stat_account(mm
, vma
->vm_flags
, len
>> PAGE_SHIFT
);
3339 perf_event_mmap(vma
);
3344 kmem_cache_free(vm_area_cachep
, vma
);
3345 return ERR_PTR(ret
);
3348 bool vma_is_special_mapping(const struct vm_area_struct
*vma
,
3349 const struct vm_special_mapping
*sm
)
3351 return vma
->vm_private_data
== sm
&&
3352 (vma
->vm_ops
== &special_mapping_vmops
||
3353 vma
->vm_ops
== &legacy_special_mapping_vmops
);
3357 * Called with mm->mmap_sem held for writing.
3358 * Insert a new vma covering the given region, with the given flags.
3359 * Its pages are supplied by the given array of struct page *.
3360 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
3361 * The region past the last page supplied will always produce SIGBUS.
3362 * The array pointer and the pages it points to are assumed to stay alive
3363 * for as long as this mapping might exist.
3365 struct vm_area_struct
*_install_special_mapping(
3366 struct mm_struct
*mm
,
3367 unsigned long addr
, unsigned long len
,
3368 unsigned long vm_flags
, const struct vm_special_mapping
*spec
)
3370 return __install_special_mapping(mm
, addr
, len
, vm_flags
, (void *)spec
,
3371 &special_mapping_vmops
);
3374 int install_special_mapping(struct mm_struct
*mm
,
3375 unsigned long addr
, unsigned long len
,
3376 unsigned long vm_flags
, struct page
**pages
)
3378 struct vm_area_struct
*vma
= __install_special_mapping(
3379 mm
, addr
, len
, vm_flags
, (void *)pages
,
3380 &legacy_special_mapping_vmops
);
3382 return PTR_ERR_OR_ZERO(vma
);
3385 static DEFINE_MUTEX(mm_all_locks_mutex
);
3387 static void vm_lock_anon_vma(struct mm_struct
*mm
, struct anon_vma
*anon_vma
)
3389 if (!test_bit(0, (unsigned long *) &anon_vma
->root
->rb_root
.rb_root
.rb_node
)) {
3391 * The LSB of head.next can't change from under us
3392 * because we hold the mm_all_locks_mutex.
3394 down_write_nest_lock(&anon_vma
->root
->rwsem
, &mm
->mmap_sem
);
3396 * We can safely modify head.next after taking the
3397 * anon_vma->root->rwsem. If some other vma in this mm shares
3398 * the same anon_vma we won't take it again.
3400 * No need of atomic instructions here, head.next
3401 * can't change from under us thanks to the
3402 * anon_vma->root->rwsem.
3404 if (__test_and_set_bit(0, (unsigned long *)
3405 &anon_vma
->root
->rb_root
.rb_root
.rb_node
))
3410 static void vm_lock_mapping(struct mm_struct
*mm
, struct address_space
*mapping
)
3412 if (!test_bit(AS_MM_ALL_LOCKS
, &mapping
->flags
)) {
3414 * AS_MM_ALL_LOCKS can't change from under us because
3415 * we hold the mm_all_locks_mutex.
3417 * Operations on ->flags have to be atomic because
3418 * even if AS_MM_ALL_LOCKS is stable thanks to the
3419 * mm_all_locks_mutex, there may be other cpus
3420 * changing other bitflags in parallel to us.
3422 if (test_and_set_bit(AS_MM_ALL_LOCKS
, &mapping
->flags
))
3424 down_write_nest_lock(&mapping
->i_mmap_rwsem
, &mm
->mmap_sem
);
3429 * This operation locks against the VM for all pte/vma/mm related
3430 * operations that could ever happen on a certain mm. This includes
3431 * vmtruncate, try_to_unmap, and all page faults.
3433 * The caller must take the mmap_sem in write mode before calling
3434 * mm_take_all_locks(). The caller isn't allowed to release the
3435 * mmap_sem until mm_drop_all_locks() returns.
3437 * mmap_sem in write mode is required in order to block all operations
3438 * that could modify pagetables and free pages without need of
3439 * altering the vma layout. It's also needed in write mode to avoid new
3440 * anon_vmas to be associated with existing vmas.
3442 * A single task can't take more than one mm_take_all_locks() in a row
3443 * or it would deadlock.
3445 * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
3446 * mapping->flags avoid to take the same lock twice, if more than one
3447 * vma in this mm is backed by the same anon_vma or address_space.
3449 * We take locks in following order, accordingly to comment at beginning
3451 * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for
3453 * - all i_mmap_rwsem locks;
3454 * - all anon_vma->rwseml
3456 * We can take all locks within these types randomly because the VM code
3457 * doesn't nest them and we protected from parallel mm_take_all_locks() by
3458 * mm_all_locks_mutex.
3460 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
3461 * that may have to take thousand of locks.
3463 * mm_take_all_locks() can fail if it's interrupted by signals.
3465 int mm_take_all_locks(struct mm_struct
*mm
)
3467 struct vm_area_struct
*vma
;
3468 struct anon_vma_chain
*avc
;
3470 BUG_ON(down_read_trylock(&mm
->mmap_sem
));
3472 mutex_lock(&mm_all_locks_mutex
);
3474 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3475 if (signal_pending(current
))
3477 if (vma
->vm_file
&& vma
->vm_file
->f_mapping
&&
3478 is_vm_hugetlb_page(vma
))
3479 vm_lock_mapping(mm
, vma
->vm_file
->f_mapping
);
3482 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3483 if (signal_pending(current
))
3485 if (vma
->vm_file
&& vma
->vm_file
->f_mapping
&&
3486 !is_vm_hugetlb_page(vma
))
3487 vm_lock_mapping(mm
, vma
->vm_file
->f_mapping
);
3490 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3491 if (signal_pending(current
))
3494 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
3495 vm_lock_anon_vma(mm
, avc
->anon_vma
);
3501 mm_drop_all_locks(mm
);
3505 static void vm_unlock_anon_vma(struct anon_vma
*anon_vma
)
3507 if (test_bit(0, (unsigned long *) &anon_vma
->root
->rb_root
.rb_root
.rb_node
)) {
3509 * The LSB of head.next can't change to 0 from under
3510 * us because we hold the mm_all_locks_mutex.
3512 * We must however clear the bitflag before unlocking
3513 * the vma so the users using the anon_vma->rb_root will
3514 * never see our bitflag.
3516 * No need of atomic instructions here, head.next
3517 * can't change from under us until we release the
3518 * anon_vma->root->rwsem.
3520 if (!__test_and_clear_bit(0, (unsigned long *)
3521 &anon_vma
->root
->rb_root
.rb_root
.rb_node
))
3523 anon_vma_unlock_write(anon_vma
);
3527 static void vm_unlock_mapping(struct address_space
*mapping
)
3529 if (test_bit(AS_MM_ALL_LOCKS
, &mapping
->flags
)) {
3531 * AS_MM_ALL_LOCKS can't change to 0 from under us
3532 * because we hold the mm_all_locks_mutex.
3534 i_mmap_unlock_write(mapping
);
3535 if (!test_and_clear_bit(AS_MM_ALL_LOCKS
,
3542 * The mmap_sem cannot be released by the caller until
3543 * mm_drop_all_locks() returns.
3545 void mm_drop_all_locks(struct mm_struct
*mm
)
3547 struct vm_area_struct
*vma
;
3548 struct anon_vma_chain
*avc
;
3550 BUG_ON(down_read_trylock(&mm
->mmap_sem
));
3551 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex
));
3553 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
3555 list_for_each_entry(avc
, &vma
->anon_vma_chain
, same_vma
)
3556 vm_unlock_anon_vma(avc
->anon_vma
);
3557 if (vma
->vm_file
&& vma
->vm_file
->f_mapping
)
3558 vm_unlock_mapping(vma
->vm_file
->f_mapping
);
3561 mutex_unlock(&mm_all_locks_mutex
);
3565 * initialise the percpu counter for VM
3567 void __init
mmap_init(void)
3571 ret
= percpu_counter_init(&vm_committed_as
, 0, GFP_KERNEL
);
3576 * Initialise sysctl_user_reserve_kbytes.
3578 * This is intended to prevent a user from starting a single memory hogging
3579 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
3582 * The default value is min(3% of free memory, 128MB)
3583 * 128MB is enough to recover with sshd/login, bash, and top/kill.
3585 static int init_user_reserve(void)
3587 unsigned long free_kbytes
;
3589 free_kbytes
= global_zone_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
3591 sysctl_user_reserve_kbytes
= min(free_kbytes
/ 32, 1UL << 17);
3594 subsys_initcall(init_user_reserve
);
3597 * Initialise sysctl_admin_reserve_kbytes.
3599 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
3600 * to log in and kill a memory hogging process.
3602 * Systems with more than 256MB will reserve 8MB, enough to recover
3603 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
3604 * only reserve 3% of free pages by default.
3606 static int init_admin_reserve(void)
3608 unsigned long free_kbytes
;
3610 free_kbytes
= global_zone_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
3612 sysctl_admin_reserve_kbytes
= min(free_kbytes
/ 32, 1UL << 13);
3615 subsys_initcall(init_admin_reserve
);
3618 * Reinititalise user and admin reserves if memory is added or removed.
3620 * The default user reserve max is 128MB, and the default max for the
3621 * admin reserve is 8MB. These are usually, but not always, enough to
3622 * enable recovery from a memory hogging process using login/sshd, a shell,
3623 * and tools like top. It may make sense to increase or even disable the
3624 * reserve depending on the existence of swap or variations in the recovery
3625 * tools. So, the admin may have changed them.
3627 * If memory is added and the reserves have been eliminated or increased above
3628 * the default max, then we'll trust the admin.
3630 * If memory is removed and there isn't enough free memory, then we
3631 * need to reset the reserves.
3633 * Otherwise keep the reserve set by the admin.
3635 static int reserve_mem_notifier(struct notifier_block
*nb
,
3636 unsigned long action
, void *data
)
3638 unsigned long tmp
, free_kbytes
;
3642 /* Default max is 128MB. Leave alone if modified by operator. */
3643 tmp
= sysctl_user_reserve_kbytes
;
3644 if (0 < tmp
&& tmp
< (1UL << 17))
3645 init_user_reserve();
3647 /* Default max is 8MB. Leave alone if modified by operator. */
3648 tmp
= sysctl_admin_reserve_kbytes
;
3649 if (0 < tmp
&& tmp
< (1UL << 13))
3650 init_admin_reserve();
3654 free_kbytes
= global_zone_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
3656 if (sysctl_user_reserve_kbytes
> free_kbytes
) {
3657 init_user_reserve();
3658 pr_info("vm.user_reserve_kbytes reset to %lu\n",
3659 sysctl_user_reserve_kbytes
);
3662 if (sysctl_admin_reserve_kbytes
> free_kbytes
) {
3663 init_admin_reserve();
3664 pr_info("vm.admin_reserve_kbytes reset to %lu\n",
3665 sysctl_admin_reserve_kbytes
);
3674 static struct notifier_block reserve_mem_nb
= {
3675 .notifier_call
= reserve_mem_notifier
,
3678 static int __meminit
init_reserve_notifier(void)
3680 if (register_hotmemory_notifier(&reserve_mem_nb
))
3681 pr_err("Failed registering memory add/remove notifier for admin reserve\n");
3685 subsys_initcall(init_reserve_notifier
);