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23 October 2021, 00:29:24 UTC
Revision 309d08d9b3a3659ab3f239d27d4e38b670b08fc9 authored by Liu Zixian on 06 December 2020, 06:15:15 UTC, committed by Linus Torvalds on 06 December 2020, 18:19:07 UTC 
mm/mmap.c: fix mmap return value when vma is merged after call_mmap()
 
On success, mmap should return the begin address of newly mapped area,
but patch "mm: mmap: merge vma after call_mmap() if possible" set
vm_start of newly merged vma to return value addr.  Users of mmap will
get wrong address if vma is merged after call_mmap().  We fix this by
moving the assignment to addr before merging vma.

We have a driver which changes vm_flags, and this bug is found by our
testcases.

Fixes: d70cec898324 ("mm: mmap: merge vma after call_mmap() if possible")
Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Hongxiang Lou <louhongxiang@huawei.com>
Cc: Hu Shiyuan <hushiyuan@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Link: https://lkml.kernel.org/r/20201203085350.22624-1-liuzixian4@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7a5bde3
Raw File
Tip revision: 309d08d9b3a3659ab3f239d27d4e38b670b08fc9 authored by Liu Zixian on 06 December 2020, 06:15:15 UTC
mm/mmap.c: fix mmap return value when vma is merged after call_mmap()
Tip revision: 309d08d
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