From: Lihong Kou koulihong@huawei.com
mainline inclusion from block-5.15 commit 3df49967f6f1d2121b0c27c381ca1c8386b1dab9 category: bugfix bugzilla: 181328 CVE: NA
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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: Yu Kuai yukuai3@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- block/blk-integrity.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/block/blk-integrity.c b/block/blk-integrity.c index 0638f4868f705..0b01fa972f1fc 100644 --- a/block/blk-integrity.c +++ b/block/blk-integrity.c @@ -436,6 +436,8 @@ void blk_integrity_unregister(struct gendisk *disk) if (!bi->profile) return;
+ /* ensure all bios are off the integrity workqueue */ + blk_flush_integrity(); disk->queue->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES; memset(bi, 0, sizeof(*bi)); }