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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 0641FC4360F for ; Mon, 1 Apr 2019 17:49:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBD9E20830 for ; Mon, 1 Apr 2019 17:49:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140983; bh=jgQLKCGqSY4d178ujtZ7TVP224+saaWtlwNFi7ZzRkA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fD2/afl09jk0RqIfNL+BxRv9z/gTm9wfiV7yLQ8wOYE+SHEnEEYb1/0cMRx/SA6H/ RfnB9bFlAfjD9Jk/KGU6wMwN79ygJqN+LjcPQ43nGlfeEUTme0wAg6tiNpa5XwByYB BGKMyHQKeLiTsVdg2lDLZQmxTGWRESPBYLFgRxr0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732458AbfDAR3k (ORCPT ); Mon, 1 Apr 2019 13:29:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:36104 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732621AbfDAR3i (ORCPT ); Mon, 1 Apr 2019 13:29:38 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 99DFF20856; Mon, 1 Apr 2019 17:29:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139778; bh=jgQLKCGqSY4d178ujtZ7TVP224+saaWtlwNFi7ZzRkA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HP/saE43DpoO66xrlxrPVUERRhSKaOMhwZhni6V6WvAHt8fLvtO0b6JZgLTLfryPI 5P2b1VA+KnjvB3MTvP0/2UMCX16SJ2/uMKMxVSGhtemPS1AfvA9WqHp6HuFgmoKmfo 1V/4z1O1yrwL8I9BX1enE3P+n798gaFMJo/wbv2g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tetsuo Handa , syzbot+53383ae265fb161ef488@syzkaller.appspotmail.com, Waiman Long , "Peter Zijlstra (Intel)" , Andrew Morton , Linus Torvalds , "Paul E. McKenney" , Thomas Gleixner , Will Deacon , Ingo Molnar Subject: [PATCH 4.4 012/131] locking/lockdep: Add debug_locks check in __lock_downgrade() Date: Mon, 1 Apr 2019 19:01:22 +0200 Message-Id: <20190401170052.846107532@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170051.645954551@linuxfoundation.org> References: <20190401170051.645954551@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Waiman Long commit 71492580571467fb7177aade19c18ce7486267f5 upstream. 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(). Debugged-by: Tetsuo Handa 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: Greg Kroah-Hartman --- kernel/locking/lockdep.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3314,6 +3314,9 @@ __lock_set_class(struct lockdep_map *loc 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,