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=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 36A64C43381 for ; Tue, 26 Mar 2019 06:47:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 072D02070B for ; Tue, 26 Mar 2019 06:47:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553582825; bh=1BlmUYHoXMCEz5q+dEcoCXwg3+xIfA+4eYIG+eWIa0s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Gr64lVh/VvKKkqTnzQR2N2rcbg7oW28Am6VJiP6hLABWTZQXLmum3qOsBwH1PQPke yo6Hy+lrpix46wreUHdOp5wBOg6LSN9sGdFHNviYM7g2NVGkAQ7Ej2O1zneEkxlARn lMMy0lLRoLBEEAH2xDTa1nyeRUE7tGqrP9r+PGT4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726278AbfCZGcc (ORCPT ); Tue, 26 Mar 2019 02:32:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:41916 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726279AbfCZGcb (ORCPT ); Tue, 26 Mar 2019 02:32:31 -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 EA7EB20823; Tue, 26 Mar 2019 06:32:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553581950; bh=1BlmUYHoXMCEz5q+dEcoCXwg3+xIfA+4eYIG+eWIa0s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GKdengsF9q7x9R4FE3vy94Rka6HGq2+SUcWC0XIGMZoWuH/dPT3du+sd/TBYZD1Uy zqmzGDdPBDPHYDPv6FyDK1RPeBfPGuqUxVhNP9bUZSMZgRjy6GgQPf8dQQulemhjBU m/VSUmSYYaYfafo4mNq8vFhGodM+Lkj6S4sCDIwY= 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 4.9 16/30] locking/lockdep: Add debug_locks check in __lock_downgrade() Date: Tue, 26 Mar 2019 15:29:55 +0900 Message-Id: <20190326042608.120387869@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190326042607.558087893@linuxfoundation.org> References: <20190326042607.558087893@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 4.9-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 @@ -3446,6 +3446,9 @@ __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,