When unmapped hw queue is remapped after CPU topology is changed, hctx->tags->cpumask has to be set after hctx->tags is setup in blk_mq_map_swqueue(), otherwise it causes null pointer dereference.
Fixes: f26cdc8536 ("blk-mq: Shared tag enhancements") Signed-off-by: Akinobu Mita <akinobu.m...@gmail.com> Cc: Keith Busch <keith.bu...@intel.com> Cc: Jens Axboe <ax...@kernel.dk> Cc: Ming Lei <tom.leim...@gmail.com> Cc: Christoph Hellwig <h...@lst.de> --- block/blk-mq.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index f2d67b4..2fd7283 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1811,7 +1811,6 @@ static void blk_mq_map_swqueue(struct request_queue *q) hctx = q->mq_ops->map_queue(q, i); cpumask_set_cpu(i, hctx->cpumask); - cpumask_set_cpu(i, hctx->tags->cpumask); ctx->index_hw = hctx->nr_ctx; hctx->ctxs[hctx->nr_ctx++] = ctx; } @@ -1851,6 +1850,14 @@ static void blk_mq_map_swqueue(struct request_queue *q) hctx->next_cpu = cpumask_first(hctx->cpumask); hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; } + + queue_for_each_ctx(q, ctx, i) { + if (!cpu_online(i)) + continue; + + hctx = q->mq_ops->map_queue(q, i); + cpumask_set_cpu(i, hctx->tags->cpumask); + } } static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/