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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 2D38EC43387 for ; Wed, 2 Jan 2019 17:07:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC96A2171F for ; Wed, 2 Jan 2019 17:07:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730592AbfABRHo (ORCPT ); Wed, 2 Jan 2019 12:07:44 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:17532 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729375AbfABRHn (ORCPT ); Wed, 2 Jan 2019 12:07:43 -0500 Received: from fsav107.sakura.ne.jp (fsav107.sakura.ne.jp [27.133.134.234]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id x02H6x1K029517; Thu, 3 Jan 2019 02:06:59 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav107.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav107.sakura.ne.jp); Thu, 03 Jan 2019 02:06:59 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav107.sakura.ne.jp) Received: from [192.168.1.8] (softbank126126163036.bbtec.net [126.126.163.36]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id x02H6w2M029513 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NO); Thu, 3 Jan 2019 02:06:58 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: INFO: rcu detected stall in ndisc_alloc_skb To: Dmitry Vyukov Cc: syzbot , David Miller , Alexey Kuznetsov , LKML , netdev , syzkaller-bugs , Hideaki YOSHIFUJI , Linux-MM References: <0000000000007beca9057e4c8c14@google.com> From: Tetsuo Handa Message-ID: Date: Thu, 3 Jan 2019 02:06:58 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/12/31 17:24, Dmitry Vyukov wrote: >>> Since this involves OOMs and looks like a one-off induced memory corruption: >>> >>> #syz dup: kernel panic: corrupted stack end in wb_workfn >>> >> >> Why? >> >> RCU stall in this case is likely to be latency caused by flooding of printk(). > > Just a hypothesis. OOMs lead to arbitrary memory corruptions, so can > cause stalls as well. But can be what you said too. I just thought > that cleaner dashboard is more useful than a large assorted pile of > crashes. If you think it's actionable in some way, feel free to undup. > We don't know why bpf tree is hitting this problem. Let's continue monitoring this problem. #syz undup