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| author | Joonsoo Kim <js1304@gmail.com> | 2012-12-12 13:51:53 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-12 17:38:33 -0800 |
| commit | 2897b4d29d9fca82a57b09b8a216a5d604966e4b (patch) | |
| tree | 0b6efa9f80c4115949cc3d26eaddfd3e7031bbae /mm/mmap.c | |
| parent | 44e33e8f95171b93968c3ac3cf8516998b1db65d (diff) | |
| download | lwn-2897b4d29d9fca82a57b09b8a216a5d604966e4b.tar.gz lwn-2897b4d29d9fca82a57b09b8a216a5d604966e4b.zip | |
mm: WARN_ON_ONCE if f_op->mmap() change vma's start address
During reviewing the source code, I found a comment which mention that
after f_op->mmap(), vma's start address can be changed. I didn't verify
that it is really possible, because there are so many f_op->mmap()
implementation. But if there are some mmap() which change vma's start
address, it is possible error situation, because we already prepare prev
vma, rb_link and rb_parent and these are related to original address.
So add WARN_ON_ONCE for finding that this situtation really happens.
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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 f940062c8d4b..9ed3a06242a0 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1488,7 +1488,11 @@ munmap_back: * * Answer: Yes, several device drivers can do it in their * f_op->mmap method. -DaveM + * Bug: If addr is changed, prev, rb_link, rb_parent should + * be updated for vma_link() */ + WARN_ON_ONCE(addr != vma->vm_start); + addr = vma->vm_start; pgoff = vma->vm_pgoff; vm_flags = vma->vm_flags; |