diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-04-13 08:07:28 -0700 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2012-08-17 15:34:58 -0400 |
| commit | 55e131e30e6fe07ab213a4ee1cf1b662fe64d90f (patch) | |
| tree | 03c8bff677d89b2132d75498b6dab7eed1c54f6f /mm/mmap.c | |
| parent | bc661f5d238569cae7ca9da01e12451b7785fb01 (diff) | |
vm: fix vm_pgoff wrap in stack expansion
commit a626ca6a656450e9f4df91d0dda238fff23285f4 upstream.
Commit 982134ba6261 ("mm: avoid wrapping vm_pgoff in mremap()") fixed
the case of a expanding mapping causing vm_pgoff wrapping when you used
mremap. But there was another case where we expand mappings hiding in
plain sight: the automatic stack expansion.
This fixes that case too.
This one also found by Robert Święcki, using his nasty system call
fuzzer tool. Good job.
Reported-and-tested-by: Robert Święcki <robert@swiecki.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[PG: .34 doesn't have perf call via 3af9e859 (in .36); adjust accordingly]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index b42b4693fb4..fe9b76ae423 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1784,10 +1784,13 @@ static int expand_downwards(struct vm_area_struct *vma, size = vma->vm_end - address; grow = (vma->vm_start - address) >> PAGE_SHIFT; - error = acct_stack_growth(vma, size, grow); - if (!error) { - vma->vm_start = address; - vma->vm_pgoff -= grow; + error = -ENOMEM; + if (grow <= vma->vm_pgoff) { + error = acct_stack_growth(vma, size, grow); + if (!error) { + vma->vm_start = address; + vma->vm_pgoff -= grow; + } } } anon_vma_unlock(vma); |