From: Ming Lei ming.lei@redhat.com

mainline inclusion from mainline-v5.15-rc6 commit commit b4459b11e84092658fa195a2587aff3b9637f0e7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RD8R CVE: CVE-2021-47498

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... b4459b11e84092658fa195a2587aff3b9637f0e7

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DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue.

But blk-mq's unquiesce may come from outside events, such as elevator switch, updating nr_requests or others, and request may come during suspend, so simply ask for blk-mq to requeue it.

Fixes one kernel panic issue when running updating nr_requests and dm-mpath suspend/resume stress test.

Cc: stable@vger.kernel.org Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com

Conflicts: drivers/md/dm-rq.c [Commit fa247089de99 ("dm: requeue IO if mapping table not yet available") has been applied in hulk code before while it was applied after this patch in mainline] Signed-off-by: Li Lingfeng lilingfeng3@huawei.com --- drivers/md/dm-rq.c | 8 ++++++++ 1 file changed, 8 insertions(+)

diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 288064e94e52..fc4eaed2d986 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -750,6 +750,14 @@ static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, struct mapped_device *md = tio->md; struct dm_target *ti = md->immutable_target;

+ /* + * blk-mq's unquiesce may come from outside events, such as + * elevator switch, updating nr_requests or others, and request may + * come during suspend, so simply ask for blk-mq to requeue it. + */ + if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) + return BLK_STS_RESOURCE; + if (unlikely(!ti)) { int srcu_idx; struct dm_table *map;