From 10845a105bbcb030647a729f1716c2309da71d33 Mon Sep 17 00:00:00 2001 From: Cong Zhang Date: Tue, 30 Dec 2025 17:17:05 +0800 Subject: [PATCH] blk-mq: skip CPU offline notify on unmapped hctx If an hctx has no software ctx mapped, blk_mq_map_swqueue() never allocates tags and leaves hctx->tags NULL. The CPU hotplug offline notifier can still run for that hctx, return early since hctx cannot hold any requests. Signed-off-by: Cong Zhang Fixes: bf0beec0607d ("blk-mq: drain I/O when all CPUs in a hctx are offline") Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 1978eef95dca..eff4f72ce83b 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3721,7 +3721,7 @@ static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node) struct blk_mq_hw_ctx, cpuhp_online); int ret = 0; - if (blk_mq_hctx_has_online_cpu(hctx, cpu)) + if (!hctx->nr_ctx || blk_mq_hctx_has_online_cpu(hctx, cpu)) return 0; /*