6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ming Lei <ming.lei@xxxxxxxxxx>
commit c25c0c9035bb8b28c844dfddeda7b8bdbcfcae95 upstream.
Commit 7b815817aa58 ("blk-mq: add helper for checking if one CPU is mapped to specified hctx")
needs to check queue mapping via tag set in hctx's cpuhp handler.
However, q->tag_set may not be setup yet when the cpuhp handler is
enabled, then kernel oops is triggered.
Fix the issue by setup queue tag_set before initializing hctx.
Cc: stable@xxxxxxxxxxxxxxx
Reported-and-tested-by: Rick Koch <mr.rickkoch@xxxxxxxxx>
Closes: https://lore.kernel.org/linux-block/CANa58eeNDozLaBHKPLxSAhEy__FPfJT_F71W=sEQw49UCrC9PQ@xxxxxxxxxxxxxx
Fixes: 7b815817aa58 ("blk-mq: add helper for checking if one CPU is mapped to specified hctx")
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241014005115.2699642-1-ming.lei@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-mq.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4307,6 +4307,12 @@ int blk_mq_init_allocated_queue(struct b
/* mark the queue as mq asap */
q->mq_ops = set->ops;
+ /*
+ * ->tag_set has to be setup before initialize hctx, which cpuphp
+ * handler needs it for checking queue mapping
+ */
+ q->tag_set = set;
+
if (blk_mq_alloc_ctxs(q))
goto err_exit;
@@ -4325,8 +4331,6 @@ int blk_mq_init_allocated_queue(struct b
INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
- q->tag_set = set;
-
q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
