From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4048015CAB for ; Tue, 8 Nov 2022 13:43:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AC32C433C1; Tue, 8 Nov 2022 13:43:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667915010; bh=x7/giUgv7EAZK+BmVoOtl36ZxalTYpP+mBzKQ4pmluU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E5Hie0MZkwbAf1l3vEyIZ942Ee/cxc2YWK8i5ySXNK7JOku7N7eDCvF8bT8VoxC+L LFEPulXJfaaUkf8ARGscaItOjo9Em48emQXIBCF3dtpUGCI8PSFjfo9AB2WkdKOgHa r5KwuIZORB6fmyIti6xv2if+vA7JlPlclU7CalQI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yu Kuai , Jan Kara , Chaitanya Kulkarni , Jens Axboe , Khazhy Kumykov Subject: [PATCH 4.14 24/40] block, bfq: protect bfqd->queued by bfqd->lock Date: Tue, 8 Nov 2022 14:39:09 +0100 Message-Id: <20221108133329.294120328@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221108133328.351887714@linuxfoundation.org> References: <20221108133328.351887714@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Yu Kuai 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(-) --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -298,6 +298,8 @@ 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); @@ -4584,8 +4586,8 @@ 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); } /*