From 18d78171c061889a9a43152f60d6a27a10fc7656 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 2 Dec 2021 17:07:16 +0800 Subject: [PATCH] blk-mq: check q->poll_stat in queue_poll_stat_show Without checking q->poll_stat in queue_poll_stat_show(), kernel panic may be caused if q->poll_stat isn't allocated. Fixes: 48b5c1fbcd8c ("block: only allocate poll_stats if there's a user of them") Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20211202090716.3292244-1-ming.lei@redhat.com Signed-off-by: Jens Axboe --- block/blk-mq-debugfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 7f27dca3a45e..3a790eb4995c 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -30,6 +30,9 @@ static int queue_poll_stat_show(void *data, struct seq_file *m) struct request_queue *q = data; int bucket; + if (!q->poll_stat) + return 0; + for (bucket = 0; bucket < (BLK_MQ_POLL_STATS_BKTS / 2); bucket++) { seq_printf(m, "read (%d Bytes): ", 1 << (9 + bucket)); print_stat(m, &q->poll_stat[2 * bucket]); -- GitLab