From c494ae149858b07d6df7614445961d34c82e461f Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Fri, 13 May 2022 10:35:06 +0800 Subject: [PATCH] block, bfq: protect 'bfqd->queued' by 'bfqd->lock' commit 181490d5321806e537dc5386db5ea640b826bf78 upstream. If bfq_schedule_dispatch() is called from bfq_idle_slice_timer_body(), then 'bfqd->queued' is read without holding 'bfqd->lock'. This is wrong since it can be wrote concurrently. Fix the problem by holding 'bfqd->lock' in such case. Signed-off-by: Yu Kuai Reviewed-by: Jan Kara Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20220513023507.2625717-2-yukuai3@huawei.com Signed-off-by: Jens Axboe Cc: Khazhy Kumykov Signed-off-by: Greg Kroah-Hartman --- block/bfq-iosched.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 962701d3f46b..c73c8b0f5e40 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -420,6 +420,8 @@ static struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd, */ void bfq_schedule_dispatch(struct bfq_data *bfqd) { + lockdep_assert_held(&bfqd->lock); + if (bfqd->queued != 0) { bfq_log(bfqd, "schedule dispatch"); blk_mq_run_hw_queues(bfqd->queue, true); @@ -6257,8 +6259,8 @@ bfq_idle_slice_timer_body(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfq_bfqq_expire(bfqd, bfqq, true, reason); schedule_dispatch: - spin_unlock_irqrestore(&bfqd->lock, flags); bfq_schedule_dispatch(bfqd); + spin_unlock_irqrestore(&bfqd->lock, flags); } /*