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 D6C23C4321D for ; Mon, 20 Aug 2018 19:29:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75B0421735 for ; Mon, 20 Aug 2018 19:29:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75B0421735 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=iogearbox.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726651AbeHTWqk (ORCPT ); Mon, 20 Aug 2018 18:46:40 -0400 Received: from www62.your-server.de ([213.133.104.62]:51194 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726077AbeHTWqj (ORCPT ); Mon, 20 Aug 2018 18:46:39 -0400 Received: from [78.46.172.2] (helo=sslproxy05.your-server.de) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.85_2) (envelope-from ) id 1frps1-0007Ph-SY; Mon, 20 Aug 2018 21:29:45 +0200 Received: from [178.197.248.15] (helo=linux.home) by sslproxy05.your-server.de with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1frps1-0004gX-NY; Mon, 20 Aug 2018 21:29:45 +0200 Subject: Re: Allocation failure with subsequent kernel crash To: whiteheadm@acm.org, Alexei Starovoitov Cc: LKML , Network Development , Ingo Molnar , Thomas Gleixner , Alexei Starovoitov References: From: Daniel Borkmann Message-ID: <05825446-e8aa-a983-3fc6-4dc8e81cba57@iogearbox.net> Date: Mon, 20 Aug 2018 21:29:45 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.100.1/24860/Mon Aug 20 18:47:04 2018) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Matthew, On 08/20/2018 08:03 AM, tedheadster wrote: > On Mon, Aug 20, 2018 at 1:22 AM, Alexei Starovoitov > wrote: >> I don't remember vzalloc issues that was fixed in this area. >> 4.14 kernel is quite old. Since then syzbot found few mem >> related bugs that were fixed. >> please try to reproduce on the latest tree. > > Alexei, > I get this panic with two very recent kernels: 4.18.0 and 4.17.14. I > do not think this has been fixed. I am still trying to bisect it, but > sometimes it takes 5 hours for the panic to occur. I've been looking into it a bit today and still am. Given you've seen this on x86_32 and also on older kernels, I presume JIT was not involved (/proc/sys/net/core/bpf_jit_enable is 0). Do you run any specific workload until you trigger this (e.g. fuzzer on BPF), or any specific event that triggers at that time after ~5hrs? Or only systemd on idle machine? Have you managed to reproduce this also elsewhere? Bisect seems indeed painful but would help tremendously; perhaps also dumping the BPF insns that are loaded at that point in time. Thanks a lot, Daniel > - Matthew Whitehead >