block: flush the integrity workqueue in blk_integrity_unregister

[ Upstream commit 3df49967f6 ]

When the integrity profile is unregistered there can still be integrity
reads queued up which could see a NULL verify_fn as shown by the race
window below:

CPU0                                    CPU1
  process_one_work                      nvme_validate_ns
    bio_integrity_verify_fn                nvme_update_ns_info
	                                     nvme_update_disk_info
	                                       blk_integrity_unregister
                                               ---set queue->integrity as 0
	bio_integrity_process
	--access bi->profile->verify_fn(bi is a pointer of queue->integity)

Before calling blk_integrity_unregister in nvme_update_disk_info, we must
make sure that there is no work item in the kintegrityd_wq. Just call
blk_flush_integrity to flush the work queue so the bug can be resolved.

Signed-off-by: Lihong Kou <koulihong@huawei.com>
[hch: split up and shortened the changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Link: https://lore.kernel.org/r/20210914070657.87677-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Lihong Kou 2021-09-14 09:06:56 +02:00 committed by Greg Kroah-Hartman
parent 1963bdb748
commit 1ef68b84bc
1 changed files with 3 additions and 0 deletions

View File

@ -430,6 +430,9 @@ void blk_integrity_unregister(struct gendisk *disk)
if (!bi->profile)
return;
/* ensure all bios are off the integrity workqueue */
blk_flush_integrity();
blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, disk->queue);
memset(bi, 0, sizeof(*bi));
}