Messages in this thread Patch in this message | | | From | Joonsoo Kim <> | Subject | [RFC PATCH] mm: WARN_ON_ONCE if f_op->mmap() change vma's start address | Date | Thu, 15 Nov 2012 02:28:52 +0900 |
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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>
diff --git a/mm/mmap.c b/mm/mmap.c index 2d94235..36567b7 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1333,7 +1333,11 @@ 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; -- 1.7.9.5
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