diff options
| author | Christoph Hellwig <hch@lst.de> | 2023-02-08 07:35:14 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-02-09 08:10:45 -0700 |
| commit | c43332fe028c252a2a28e46be70a530f64fc3c9d (patch) | |
| tree | a92d675fb0c4f51de51836f9665f0398b6fc8fe3 /block/blk-throttle.c | |
| parent | a872818f484d69944c10be555941b2a73f6e1d4f (diff) | |
blk-cgroup: delay calling blkcg_exit_disk until disk_release
While del_gendisk ensures there is no outstanding I/O on the queue,
it can't prevent block layer users from building new I/O.
This leads to a NULL ->root_blkg reference in bio_associate_blkg when
allocating a new bio on a shut down file system. Delay freeing the
blk-cgroup subsystems from del_gendisk until disk_release to make
sure the blkg and throttle information is still avaŃ–lable for bio
submitters, even if those bios will immediately fail.
This now can cause a case where disk_release is called on a disk
that hasn't been added. That's mostly harmless, except for a case
in blk_throttl_exit that now needs to check for a NULL ->td pointer.
Fixes: 178fa7d49815 ("blk-cgroup: delay blk-cgroup initialization until add_disk")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230208063514.171485-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-throttle.c')
| -rw-r--r-- | block/blk-throttle.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 902203bdddb4..e7bd7050d684 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2411,7 +2411,8 @@ void blk_throtl_exit(struct gendisk *disk) { struct request_queue *q = disk->queue; - BUG_ON(!q->td); + if (!q->td) + return; del_timer_sync(&q->td->service_queue.pending_timer); throtl_shutdown_wq(q); blkcg_deactivate_policy(disk, &blkcg_policy_throtl); |