| From 181490d5321806e537dc5386db5ea640b826bf78 Mon Sep 17 00:00:00 2001 |
| From: Yu Kuai <yukuai3@huawei.com> |
| Date: Fri, 13 May 2022 10:35:06 +0800 |
| Subject: block, bfq: protect 'bfqd->queued' by 'bfqd->lock' |
| |
| From: Yu Kuai <yukuai3@huawei.com> |
| |
| 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 <yukuai3@huawei.com> |
| Reviewed-by: Jan Kara <jack@suse.cz> |
| Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> |
| Link: https://lore.kernel.org/r/20220513023507.2625717-2-yukuai3@huawei.com |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Cc: Khazhy Kumykov <khazhy@chromium.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| block/bfq-iosched.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/block/bfq-iosched.c |
| +++ b/block/bfq-iosched.c |
| @@ -421,6 +421,8 @@ static struct bfq_io_cq *bfq_bic_lookup( |
| */ |
| 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); |
| @@ -6269,8 +6271,8 @@ bfq_idle_slice_timer_body(struct bfq_dat |
| 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); |
| } |
| |
| /* |
