From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751204AbdKHIki (ORCPT ); Wed, 8 Nov 2017 03:40:38 -0500 Received: from merlin.infradead.org ([205.233.59.134]:45726 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751126AbdKHIkh (ORCPT ); Wed, 8 Nov 2017 03:40:37 -0500 Date: Wed, 8 Nov 2017 09:40:31 +0100 From: Peter Zijlstra To: Dmitry Vyukov Cc: syzbot , LKML , Ingo Molnar , syzkaller-bugs@googlegroups.com Subject: Re: general protection fault in lockdep_invariant_state (2) Message-ID: <20171108084031.GX3165@worktop.lehotels.local> References: <001a114498f6446843055d744c3a@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 08, 2017 at 09:19:53AM +0100, Dmitry Vyukov wrote: > > R13: 0000000000402260 R14: 00000000004022f0 R15: 0000000000000000 > > kasan: CONFIG_KASAN_INLINE enabled > > kasan: GPF could be caused by NULL-ptr deref or user memory access > > general protection fault: 0000 [#1] SMP KASAN > > Dumping ftrace buffer: > > (ftrace buffer empty) > > Modules linked in: > > CPU: 3 PID: 2982 Comm: syzkaller521009 Not tainted 4.14.0-rc7-next-20171103+ > > #10 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > > task: ffff88003d6b25c0 task.stack: ffff88003abd0000 > > RIP: 0010:invalidate_xhlock kernel/locking/lockdep.c:4719 [inline] > > RIP: 0010:lockdep_invariant_state+0xd6/0x120 kernel/locking/lockdep.c:4793 Does this help? diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index db933d063bfc..da2904418599 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4793,7 +4793,8 @@ void lockdep_invariant_state(bool force) * Verify the former, enforce the latter. */ WARN_ON_ONCE(!force && current->lockdep_depth); - invalidate_xhlock(&xhlock(current->xhlock_idx)); + if (current->xhlocks) + invalidate_xhlock(&xhlock(current->xhlock_idx)); } static int cross_lock(struct lockdep_map *lock)