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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-04-13 08:07:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-04-13 08:07:28 -0700 |
| commit | a626ca6a656450e9f4df91d0dda238fff23285f4 (patch) | |
| tree | 7de7fabc83baf1312805d9b5f28f01d1adf3f7fd /mm/mmap.c | |
| parent | 60d48c1e67dc8de0676453de18adba1768fb6fab (diff) | |
| download | linux-stable-a626ca6a656450e9f4df91d0dda238fff23285f4.tar.gz linux-stable-a626ca6a656450e9f4df91d0dda238fff23285f4.tar.bz2 linux-stable-a626ca6a656450e9f4df91d0dda238fff23285f4.zip | |
vm: fix vm_pgoff wrap in stack expansion
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>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 2ec8eb5a9cdd..8c05e5b43b69 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1814,11 +1814,14 @@ 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; - perf_event_mmap(vma); + error = -ENOMEM; + if (grow <= vma->vm_pgoff) { + error = acct_stack_growth(vma, size, grow); + if (!error) { + vma->vm_start = address; + vma->vm_pgoff -= grow; + perf_event_mmap(vma); + } } } vma_unlock_anon_vma(vma); |