diff options
| author | Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> | 2021-07-06 23:40:34 +0900 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-07-23 10:18:25 -0600 |
| commit | 3ce6e1f662a910970880188ea7bfd00542bd3934 (patch) | |
| tree | fc2ed8f0a332beb2ece07dee8947808823dfb8cb /block/blk-mq-sched.c | |
| parent | 7054133da39a82c1dc44ce796f13a7cb0d6a0b3c (diff) | |
loop: reintroduce global lock for safe loop_validate_file() traversal
Commit 6cc8e7430801fa23 ("loop: scale loop device by introducing per
device lock") re-opened a race window for NULL pointer dereference at
loop_validate_file() where commit 310ca162d779efee ("block/loop: Use
global lock for ioctl() operation.") has closed.
Although we need to guarantee that other loop devices will not change
during traversal, we can't take remote "struct loop_device"->lo_mutex
inside loop_validate_file() in order to avoid AB-BA deadlock. Therefore,
introduce a global lock dedicated for loop_validate_file() which is
conditionally taken before local "struct loop_device"->lo_mutex is taken.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 6cc8e7430801fa23 ("loop: scale loop device by introducing per device lock")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq-sched.c')
0 files changed, 0 insertions, 0 deletions