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| author | Johannes Weiner <hannes@cmpxchg.org> | 2009-01-06 14:40:31 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:59:10 -0800 |
| commit | dcd4a049b9751828c516c59709f3fdf50436df85 (patch) | |
| tree | 126fe11368da94f0c2e11ed586a870fa1b02f0a6 | |
| parent | 084f71ae5ceeb16734d8ac47559d3c718456a865 (diff) | |
| download | linux-dcd4a049b9751828c516c59709f3fdf50436df85.tar.gz linux-dcd4a049b9751828c516c59709f3fdf50436df85.tar.bz2 linux-dcd4a049b9751828c516c59709f3fdf50436df85.zip | |
mm: check for no mmaps in exit_mmap()
When dup_mmap() ooms we can end up with mm->mmap == NULL. The error
path does mmput() and unmap_vmas() gets a NULL vma which it
dereferences.
In exit_mmap() there is nothing to do at all for this case, we can
cancel the callpath right there.
[akpm@linux-foundation.org: add sorely-needed comment]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/mmap.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 1f97d8aa9b05..a910c045cfd4 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2090,6 +2090,9 @@ void exit_mmap(struct mm_struct *mm) arch_exit_mmap(mm); mmu_notifier_release(mm); + if (!mm->mmap) /* Can happen if dup_mmap() received an OOM */ + return; + if (mm->locked_vm) { vma = mm->mmap; while (vma) { |