6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei ming.lei@redhat.com
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@vger.kernel.org Reported-and-tested-by: Rick Koch mr.rickkoch@gmail.com Closes: https://lore.kernel.org/linux-block/CANa58eeNDozLaBHKPLxSAhEy__FPfJT_F71W=sE... Fixes: 7b815817aa58 ("blk-mq: add helper for checking if one CPU is mapped to specified hctx") Signed-off-by: Ming Lei ming.lei@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: John Garry john.g.garry@oracle.com Link: https://lore.kernel.org/r/20241014005115.2699642-1-ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-mq.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4453,6 +4453,12 @@ 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;
@@ -4471,8 +4477,6 @@ 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; blk_mq_update_poll_flag(q);