diff options
| author | Mike Rapoport (Microsoft) <rppt@kernel.org> | 2026-05-13 11:14:16 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-06-03 01:22:17 +0300 |
| commit | 0496a59745b0723ea74274db16fd5c8b1379b9a9 (patch) | |
| tree | bff7e2e6fde3d6d32f523728fcc2efc4e755b780 /include/linux | |
| parent | 59f19bf6f119eecfa16355186b593abba8eb5198 (diff) | |
| download | linux-0496a59745b0723ea74274db16fd5c8b1379b9a9.tar.xz | |
userfaultfd: ensure mremap_userfaultfd_fail() releases mmap_changing
Sashiko says:
mremap_userfaultfd_prep() increments ctx->mmap_changing to stall
concurrent operations, but mremap_userfaultfd_fail() does not
decrement it before dropping the context reference.
If an mremap operation fails, ctx->mmap_changing remains elevated. This
will causes subsequent userfaultfd operations like a UFFDIO_COPY to fail
with -EAGAIN.
Decrement ctx->mmap_changing in mremap_userfaultfd_fail().
Link: https://sashiko.dev/#/patchset/20260430113512.115938-1-rppt@kernel.org
Link: https://lore.kernel.org/20260513081416.495963-1-rppt@kernel.org
Fixes: df2cc96e7701 ("userfaultfd: prevent non-cooperative events vs mcopy_atomic races")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux')
0 files changed, 0 insertions, 0 deletions