diff options
| author | Suren Baghdasaryan <surenb@google.com> | 2023-02-27 09:36:26 -0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-05 20:03:01 -0700 |
| commit | 444eeb17437a0ef526c606e9141a415d3b7dfddd (patch) | |
| tree | 4a62168d40f3df1e5bd42084e790af170551a07c /mm/memory.c | |
| parent | 17c05f18e54158a3eed0c22c85b7a756b63dcc01 (diff) | |
| download | linux-444eeb17437a0ef526c606e9141a415d3b7dfddd.tar.gz | |
mm: prevent userfaults to be handled under per-vma lock
Due to the possibility of handle_userfault dropping mmap_lock, avoid fault
handling under VMA lock and retry holding mmap_lock. This can be handled
more gracefully in the future.
Link: https://lkml.kernel.org/r/20230227173632.3292573-28-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c index 70f4b1222e5d0..55ac9cdfd3983 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5266,6 +5266,15 @@ retry: if (!vma_start_read(vma)) goto inval; + /* + * Due to the possibility of userfault handler dropping mmap_lock, avoid + * it for now and fall back to page fault handling under mmap_lock. + */ + if (userfaultfd_armed(vma)) { + vma_end_read(vma); + goto inval; + } + /* Check since vm_start/vm_end might change before we lock the VMA */ if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { vma_end_read(vma); |