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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 14E30C43461 for ; Tue, 8 Sep 2020 19:03:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4CAE20C09 for ; Tue, 8 Sep 2020 19:03:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599591804; bh=bmQdkNH3AtKy4aJrZ0hiO2G1mnDDEJjfOONUdQ49HW8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=S0E8TMN9k8ZPnv0a3wfTZ8OomImpZn3O0MWxD+KuZ8V/R9sxbpUAVOhjFvyzlpA3g UP2H/8LVM+38BAlNNzjA5sY5uGLzEIPEP8mpE89mbuwGqexu/MY3G0XPrjP2KRFW8B PGnJIMiKQN+0exIhmhORRHWeGcKVbMhFh3tGKjdM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731684AbgIHTDW (ORCPT ); Tue, 8 Sep 2020 15:03:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:53538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731267AbgIHQH0 (ORCPT ); Tue, 8 Sep 2020 12:07:26 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6575E23E26; Tue, 8 Sep 2020 15:47:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599580028; bh=bmQdkNH3AtKy4aJrZ0hiO2G1mnDDEJjfOONUdQ49HW8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EXMZs8fnm/ai3Eub59ODnLGc6FvEGfThXGFRqzEVPgXvS6xBr8vstD82wNsrmItCA qsqyr+MPl6ImnJCZiiaeAMEkOUClB0fz1r50OKup/RtiOFR2xCY+FyHSdJXs6aMg77 O67hVln+oGa6ZYSDBqDP2J4HLYcilG3f87GekqRc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tejun Heo , Jens Axboe Subject: [PATCH 5.4 110/129] blk-iocost: ioc_pd_free() shouldnt assume irq disabled Date: Tue, 8 Sep 2020 17:25:51 +0200 Message-Id: <20200908152235.335513954@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152229.689878733@linuxfoundation.org> References: <20200908152229.689878733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tejun Heo commit 5aeac7c4b16069aae49005f0a8d4526baa83341b upstream. ioc_pd_free() grabs irq-safe ioc->lock without ensuring that irq is disabled when it can be called with irq disabled or enabled. This has a small chance of causing A-A deadlocks and triggers lockdep splats. Use irqsave operations instead. Signed-off-by: Tejun Heo Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/blk-iocost.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -2074,14 +2074,15 @@ static void ioc_pd_free(struct blkg_poli { struct ioc_gq *iocg = pd_to_iocg(pd); struct ioc *ioc = iocg->ioc; + unsigned long flags; if (ioc) { - spin_lock(&ioc->lock); + spin_lock_irqsave(&ioc->lock, flags); if (!list_empty(&iocg->active_list)) { propagate_active_weight(iocg, 0, 0); list_del_init(&iocg->active_list); } - spin_unlock(&ioc->lock); + spin_unlock_irqrestore(&ioc->lock, flags); hrtimer_cancel(&iocg->waitq_timer); hrtimer_cancel(&iocg->delay_timer);