From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2A1EC432BE for ; Wed, 1 Sep 2021 12:39:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 787C2610FD for ; Wed, 1 Sep 2021 12:39:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344080AbhIAMjF (ORCPT ); Wed, 1 Sep 2021 08:39:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:35682 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344160AbhIAMhL (ORCPT ); Wed, 1 Sep 2021 08:37:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5F34E610E8; Wed, 1 Sep 2021 12:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1630499642; bh=4gyxiK/n9KX7xbOFQ97wN+1L5/y2dlCEb5MXDADMqBk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YKNbTsHbnhPnzMr8KMggcq/ITVO8ZDDnk5g8MDg9toEo7SOPGav+sHFTr4o2mc+Y/ 9tScKUQT7M3sV1cPwmGGfmpYcsJs3ulJ+mHsuvQh1Rysy9aof1BLWc1i+L7amVvirI ZvCfwB9xczxc1r48LZUNJ+ktfQevCq6Y8+eCKrn8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tejun Heo , Bruno Goncalves , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 5.10 009/103] blk-iocost: fix lockdep warning on blkcg->lock Date: Wed, 1 Sep 2021 14:27:19 +0200 Message-Id: <20210901122300.840854533@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210901122300.503008474@linuxfoundation.org> References: <20210901122300.503008474@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ming Lei [ Upstream commit 11431e26c9c43fa26f6b33ee1a90989f57b86024 ] blkcg->lock depends on q->queue_lock which may depend on another driver lock required in irq context, one example is dm-thin: Chain exists of: &pool->lock#3 --> &q->queue_lock --> &blkcg->lock Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&blkcg->lock); local_irq_disable(); lock(&pool->lock#3); lock(&q->queue_lock); lock(&pool->lock#3); Fix the issue by using spin_lock_irq(&blkcg->lock) in ioc_weight_write(). Cc: Tejun Heo Reported-by: Bruno Goncalves Link: https://lore.kernel.org/linux-block/CA+QYu4rzz6079ighEanS3Qq_Dmnczcf45ZoJoHKVLVATTo1e4Q@mail.gmail.com/T/#u Signed-off-by: Ming Lei Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20210803070608.1766400-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-iocost.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index b7d8a954d99c..e95b93f72bd5 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -3039,19 +3039,19 @@ static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf, if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX) return -EINVAL; - spin_lock(&blkcg->lock); + spin_lock_irq(&blkcg->lock); iocc->dfl_weight = v * WEIGHT_ONE; hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { struct ioc_gq *iocg = blkg_to_iocg(blkg); if (iocg) { - spin_lock_irq(&iocg->ioc->lock); + spin_lock(&iocg->ioc->lock); ioc_now(iocg->ioc, &now); weight_updated(iocg, &now); - spin_unlock_irq(&iocg->ioc->lock); + spin_unlock(&iocg->ioc->lock); } } - spin_unlock(&blkcg->lock); + spin_unlock_irq(&blkcg->lock); return nbytes; } -- 2.30.2