I have not been able to reproduce this issue. But you may want to try
the following patch (applies on top of v5.1-rc3):
Subject: [PATCH] block: Fix blk_mq_try_issue_directly()
If blk_mq_try_issue_directly() returns BLK_STS*_RESOURCE that means that
the request has not been queued and that the caller should retry to submit
the request. Both blk_mq_request_bypass_insert() and
blk_mq_sched_insert_request() guarantee that a request will be processed.
Hence return BLK_STS_OK if one of these functions is called. This patch
avoids that blk_mq_dispatch_rq_list() crashes when using dm-mpath.
Reported-by: Laurence Oberman <loberman@xxxxxxxxxx>
Fixes: 7f556a44e61d ("blk-mq: refactor the code of issue request directly") # v5.0.
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
block/blk-mq.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 652d0c6d5945..b2c20dce8a30 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1859,16 +1859,11 @@ blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
case BLK_STS_RESOURCE:
if (force) {
blk_mq_request_bypass_insert(rq, run_queue);
- /*
- * We have to return BLK_STS_OK for the DM
- * to avoid livelock. Otherwise, we return
- * the real result to indicate whether the
- * request is direct-issued successfully.
- */
- ret = bypass ? BLK_STS_OK : ret;
+ ret = BLK_STS_OK;
} else if (!bypass) {
blk_mq_sched_insert_request(rq, false,
run_queue, false);
+ ret = BLK_STS_OK;
}
I would move the ret assignment here after the condition statement.
