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authorLokesh Gidra <lokeshgidra@google.com>2024-03-21 16:58:18 -0700
committerAndrew Morton <akpm@linux-foundation.org>2024-03-26 11:07:23 -0700
commit30af24facf0aed12dec23bdf6eac6a907f88306a (patch)
tree35d01113a579cf8f2543cb0e9a6a3a63cd6ac291 /mm
parent0a69b6b3a026543bc215ccc866d0aea5579e6ce2 (diff)
userfaultfd: fix deadlock warning when locking src and dst VMAs
Use down_read_nested() to avoid the warning. Link: https://lkml.kernel.org/r/20240321235818.125118-1-lokeshgidra@google.com Fixes: 867a43a34ff8 ("userfaultfd: use per-vma locks in userfaultfd operations") Reported-by: syzbot+49056626fe41e01f2ba7@syzkaller.appspotmail.com Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jann Horn <jannh@google.com> [Bug #2] Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Nicolas Geoffray <ngeoffray@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/userfaultfd.c3
1 files changed, 2 insertions, 1 deletions
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;