]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm/mmap.c: fix mmap return value when vma is merged after call_mmap()
authorLiu Zixian <liuzixian4@huawei.com>
Sun, 6 Dec 2020 06:15:15 +0000 (22:15 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sun, 6 Dec 2020 18:19:07 +0000 (10:19 -0800)
commit309d08d9b3a3659ab3f239d27d4e38b670b08fc9
tree989f191d033e2a58ba5d546bc2782036c9daf173
parent7a5bde37983d37783161681ff7c6122dfd081791
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>
mm/mmap.c