diff options
| author | Suren Baghdasaryan <surenb@google.com> | 2023-07-08 12:12:10 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-07-08 14:08:02 -0700 |
| commit | c137381f71aec755fbf47cd4e9bd4dce752c054c (patch) | |
| tree | 13f8dc7926e331b638e943a6759f9be7c87b7484 /mm/mmap.c | |
| parent | 7fcd473a6455450428795d20db7afd2691c92336 (diff) | |
mm: lock a vma before stack expansion
With recent changes necessitating mmap_lock to be held for write while
expanding a stack, per-VMA locks should follow the same rules and be
write-locked to prevent page faults into the VMA being expanded. Add
the necessary locking.
Cc: stable@vger.kernel.org
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 204ddcd52625..c66e4622a557 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1977,6 +1977,8 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address) return -ENOMEM; } + /* Lock the VMA before expanding to prevent concurrent page faults */ + vma_start_write(vma); /* * vma->vm_start/vm_end cannot change under us because the caller * is required to hold the mmap_lock in read mode. We need the @@ -2064,6 +2066,8 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) return -ENOMEM; } + /* Lock the VMA before expanding to prevent concurrent page faults */ + vma_start_write(vma); /* * vma->vm_start/vm_end cannot change under us because the caller * is required to hold the mmap_lock in read mode. We need the |