This is a note to let you know that I've just added the patch titled block: flush the integrity workqueue in blk_integrity_unregister to the 5.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: block-flush-the-integrity-workqueue-in-blk_integrity.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 725400c5318c24b36514d6df734924cd8db86056 Author: Lihong Kou <koulihong@xxxxxxxxxx> Date: Tue Sep 14 09:06:56 2021 +0200 block: flush the integrity workqueue in blk_integrity_unregister [ Upstream commit 3df49967f6f1d2121b0c27c381ca1c8386b1dab9 ] 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@xxxxxxxxxx> [hch: split up and shortened the changelog] Signed-off-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20210914070657.87677-3-hch@xxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/block/blk-integrity.c b/block/blk-integrity.c index e9f943de377a..9e83159f5a52 100644 --- a/block/blk-integrity.c +++ b/block/blk-integrity.c @@ -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)); }