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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 88FDFC43381 for ; Tue, 26 Mar 2019 06:35:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 533AB2070B for ; Tue, 26 Mar 2019 06:35:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553582109; bh=urFK40PDnA0z6rhdoGJiTQOLOLUSwS7kHZ/fxGZl0Ws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2Te4nr0peHfRKMjqo26zG7ddWULbHXKb6ZvGKXMbgkYzBzxPtuOktBeY11GNjkG8v XX9jiG+ez5yOMtUl71jAevTw2bSt9pmjtaA7CVkv9IHDYjQ0mnxbZ086AXkjvYu9NB vjnxGeIbZmFyBqkqy64Uum7splZ8mGgpBXn/EU1Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731986AbfCZGfI (ORCPT ); Tue, 26 Mar 2019 02:35:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:46142 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731566AbfCZGfC (ORCPT ); Tue, 26 Mar 2019 02:35:02 -0400 Received: from localhost (unknown [104.132.152.111]) (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 4BFBF20856; Tue, 26 Mar 2019 06:35:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553582102; bh=urFK40PDnA0z6rhdoGJiTQOLOLUSwS7kHZ/fxGZl0Ws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WmUvPip2D/LtqIi7KNnx4rJ+9Y1wWP1+AGXiBeMoEznOCA7wBxdIKXWLHHbk1H5q2 8qsmHDUmtal7DYQeoGlyK2jDwlpus7Emk7ZsDcYgOphRGrEbJgj61RyKWOUa5iH6Bw NKaVDBsqeGb8HiKscuNVWlwcst2pVCbYYrNkK3G8= 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 4.14 27/41] locking/lockdep: Add debug_locks check in __lock_downgrade() Date: Tue, 26 Mar 2019 15:30:04 +0900 Message-Id: <20190326042651.410065581@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190326042649.889479098@linuxfoundation.org> References: <20190326042649.889479098@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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-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 @@ -3650,6 +3650,9 @@ __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,