From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752984AbdJTLOO (ORCPT ); Fri, 20 Oct 2017 07:14:14 -0400 Received: from foss.arm.com ([217.140.101.70]:40782 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752928AbdJTLON (ORCPT ); Fri, 20 Oct 2017 07:14:13 -0400 Date: Fri, 20 Oct 2017 12:14:08 +0100 From: Mark Rutland To: Wei Wei Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, edumazet@google.com, davem@davemloft.net, willemb@google.com, syzkaller@googlegroups.com Subject: Re: v4.14-rc3/arm64 DABT exception in atomic_inc() / __skb_clone() Message-ID: <20171020111408.edj24tztxdptte5r@lakrids.cambridge.arm.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 19, 2017 at 10:16:08PM -0400, Wei Wei wrote: > Hi all, Hi, > I have fuzzed v4.14-rc3 using syzkaller and found a bug similar to that one [1]. > But the call trace isn’t the same. The atomic_inc() might handle a corrupted > skb_buff. > > The logs and config have been uploaded to my github repo [2]. > > [1] https://lkml.org/lkml/2017/10/2/216 > [2] https://github.com/dotweiba/skb_clone_atomic_inc_bug These do look very similar to what I was hitting; all appear to be misaligned atomics in the same path. I see that you have some empty repro files in [2]. If you have any reproducers, would you mind sharing them? If any of those are smaller or more reliable than the one I was able to generate [3], it might make it more obvious what's going on, and/or make it simpler to come up with a plain C reproducer. Thanks, Mark. [3] https://www.kernel.org/pub/linux/kernel/people/mark/bugs/20171002-skb_clone-misaligned-atomic/syzkaller.repro