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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 E040AC3A5AB for ; Thu, 5 Sep 2019 03:07:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B806420693 for ; Thu, 5 Sep 2019 03:07:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="dJ/kcZiL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731064AbfIEDHp (ORCPT ); Wed, 4 Sep 2019 23:07:45 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:36058 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729919AbfIEDHp (ORCPT ); Wed, 4 Sep 2019 23:07:45 -0400 Received: by mail-pf1-f194.google.com with SMTP id y22so758574pfr.3 for ; Wed, 04 Sep 2019 20:07:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=bv8aLyZNsRQTuIGo9WBDbNKWSEWFm7lp2gBa2Tmb/+Y=; b=dJ/kcZiLoIWOyyw6EfFPZeTXLsTZNg9iDTuBuXEqB+kjja/lH3LAkPeOLFJAsOWKCc C/z6F3GUxZ/IB7EDbx9Q1NptWBRZprPFMK5DtN2adq5zQx7CI500p6v2GhBCDewaN/05 GM3lH33ZsVbgMrZZVG7Bp2m/1UrW4z8G9ztPyacNo9gFE1b5xSmhBxudlHqFKmPtOldy IoCm5mHDORE/jjJKkueXfSaUX72IOBNrHiwt63UBkSpiASgBZkMzI2rpreM5GrrxVkGa flKKFL1ofwgPuI9Ap/pt1WBEWqVlX4gFTOGVEeJUxSVIbk9YhecfTtoYN4CrlRp3uy9X h9ZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=bv8aLyZNsRQTuIGo9WBDbNKWSEWFm7lp2gBa2Tmb/+Y=; b=rq566btQ9/0KfVve+c1n7gexQRGvSXObFE4Rqpi7Um5Srze5Mg9Cb4WwyTpnLyNz0q G/zd9Np/EDtrqgd8RjRMaCXMBfu5EkBTkhPnpjFM4rGJtfL/CUrH1/qEZ+6WWKJKUR8Y r2E4yy7FlL1t7pAiSXifwW/NnhQ5yxVjho8gaAg0vZO0NTzbBYng829u3sI3yZTnrHg1 J+06ppYw/h8b3SlvPBr5byWxj45M2vjipmYQTYr15OZ5o60iSZ79owKUYVnLU59xQuGT dflnHxpNmPN7KbP/W4NcbHk1poU1W0kGFb2wrIbIQ9NfKw/V3ODITeG+1WDKXEONMR5c QtcA== X-Gm-Message-State: APjAAAVVNCtKQsWaydMDBIXtvWz4HpOlCOJBN6YNBU+kUw6XjckRAkPY mxntDQxMOEkGPWm+i3jNDVDNK9YPuWkqig== X-Google-Smtp-Source: APXvYqyrb1FUlMJrBM7epNFloFgKYqsJf+HLa9tMPIRmvfvzIaUcesBgOzq7JDUpTYhk02fyisWnxg== X-Received: by 2002:aa7:8d12:: with SMTP id j18mr1128275pfe.33.1567652864452; Wed, 04 Sep 2019 20:07:44 -0700 (PDT) Received: from baolinwangubtpc.spreadtrum.com ([117.18.48.82]) by smtp.gmail.com with ESMTPSA id x9sm425686pgp.75.2019.09.04.20.07.41 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 04 Sep 2019 20:07:43 -0700 (PDT) From: Baolin Wang To: stable@vger.kernel.org, peterz@infradead.org, mingo@redhat.com Cc: longman@redhat.com, arnd@arndb.de, baolin.wang@linaro.org, orsonzhai@gmail.com, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org Subject: [BACKPORT 4.14.y v2 2/6] locking/lockdep: Add debug_locks check in __lock_downgrade() Date: Thu, 5 Sep 2019 11:07:14 +0800 Message-Id: <7d3d221015cd343df47de4a68ed4776aca2ca0ab.1567649729.git.baolin.wang@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Waiman Long [Upstream commit 513e1073d52e55b8024b4f238a48de7587c64ccf] Tetsuo Handa had reported he saw an incorrect "downgrading a read lock" warning right after a previous lockdep warning. It is likely that the previous warning turned off lock debugging causing the lockdep to have inconsistency states leading to the lock downgrade warning. Fix that by add a check for debug_locks at the beginning of __lock_downgrade(). Reported-by: Tetsuo Handa Reported-by: syzbot+53383ae265fb161ef488@syzkaller.appspotmail.com Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Link: https://lkml.kernel.org/r/1547093005-26085-1-git-send-email-longman@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Baolin Wang --- kernel/locking/lockdep.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 565005a..5c370c6 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3650,6 +3650,9 @@ static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, unsigned int depth; int i; + if (unlikely(!debug_locks)) + return 0; + depth = curr->lockdep_depth; /* * This function is about (re)setting the class of a held lock, -- 1.7.9.5