Messages in this thread Patch in this message | | | Date | Thu, 21 Mar 2024 16:58:18 -0700 | Subject | [PATCH] userfaultfd: fix deadlock warning when locking src and dst VMAs | From | Lokesh Gidra <> |
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Use down_read_nested() to avoid the warning.
Reported-by: syzbot+49056626fe41e01f2ba7@syzkaller.appspotmail.com Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> --- mm/userfaultfd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 712160cd41ec..3c3539c573e7 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -1444,7 +1444,8 @@ static int uffd_move_lock(struct mm_struct *mm, */ down_read(&(*dst_vmap)->vm_lock->lock); if (*dst_vmap != *src_vmap) - down_read(&(*src_vmap)->vm_lock->lock); + down_read_nested(&(*src_vmap)->vm_lock->lock, + SINGLE_DEPTH_NESTING); } mmap_read_unlock(mm); return err; -- 2.44.0.396.g6e790dbe36-goog
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