Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754038AbdGSJq3 (ORCPT ); Wed, 19 Jul 2017 05:46:29 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37712 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753443AbdGSJq0 (ORCPT ); Wed, 19 Jul 2017 05:46:26 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Hutchings , Sasha Levin , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , a.p.zijlstra@chello.nl, Ingo Molnar Subject: [PATCH 4.12 41/84] tools/lib/lockdep: Reduce MAX_LOCK_DEPTH to avoid overflowing lock_chain/: Depth Date: Wed, 19 Jul 2017 11:43:47 +0200 Message-Id: <20170719092323.983014877@linuxfoundation.org> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170719092322.362625377@linuxfoundation.org> References: <20170719092322.362625377@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1832 Lines: 53 4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings commit 98dcea0cfd04e083ac74137ceb9a632604740e2d upstream. liblockdep has been broken since commit 75dd602a5198 ("lockdep: Fix lock_chain::base size"), as that adds a check that MAX_LOCK_DEPTH is within the range of lock_chain::depth and in liblockdep it is much too large. That should have resulted in a compiler error, but didn't because: - the check uses ARRAY_SIZE(), which isn't yet defined in liblockdep so is assumed to be an (undeclared) function - putting a function call inside a BUILD_BUG_ON() expression quietly turns it into some nonsense involving a variable-length array It did produce a compiler warning, but I didn't notice because liblockdep already produces too many warnings if -Wall is enabled (which I'll fix shortly). Even before that commit, which reduced lock_chain::depth from 8 bits to 6, MAX_LOCK_DEPTH was too large. Signed-off-by: Ben Hutchings Signed-off-by: Sasha Levin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/20170525130005.5947-3-alexander.levin@verizon.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- tools/lib/lockdep/uinclude/linux/lockdep.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/tools/lib/lockdep/uinclude/linux/lockdep.h +++ b/tools/lib/lockdep/uinclude/linux/lockdep.h @@ -8,7 +8,7 @@ #include #include -#define MAX_LOCK_DEPTH 2000UL +#define MAX_LOCK_DEPTH 63UL #define asmlinkage #define __visible