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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 04346CA9EBD for ; Fri, 25 Oct 2019 13:50:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCD0020679 for ; Fri, 25 Oct 2019 13:50:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="0cQoRyAc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504933AbfJYNur (ORCPT ); Fri, 25 Oct 2019 09:50:47 -0400 Received: from mail-io1-f65.google.com ([209.85.166.65]:39816 "EHLO mail-io1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2502085AbfJYNur (ORCPT ); Fri, 25 Oct 2019 09:50:47 -0400 Received: by mail-io1-f65.google.com with SMTP id y12so2490838ioa.6 for ; Fri, 25 Oct 2019 06:50:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=pHXHkRZYMYriBwnGx1XM0y5ekEDpj7Yqy5vMy8KNTfI=; b=0cQoRyAcYNQaeNht9WUlKmJ4thYDBCv0oGZ90WqeIlTJc/i2dvhTHtH9lLGX+i9xMJ JNUEzJItBVmQ/pue/RpcicBZXfmgvVyCD8ta53VyAsFNMWZnIX5Hq2d5dhnxFf0DinkA b61XpECUWEWOztP77nH4HlIkiQTTuLjYxQ3AxvK5A/3VSPv5faRfmsint3I440JUecgz VzrV+RQbGZTBDQzjq9/g6PGatAMbhG+fOWV26uaBrDiAtHwbI3WV+jzo0ZoFkL9zjS/h 4qlhySnaCAJkPLVAjF8sVbNc3Voxzx9dYl5rXOho+EJRi6a8Mxx2LDtpFri1YyapPvdm slBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=pHXHkRZYMYriBwnGx1XM0y5ekEDpj7Yqy5vMy8KNTfI=; b=KTPg8sXFwdbhSpRyHuTVr3MhiNqASsjw7FBEn29CFLMdURfIiGiysmqsx8OcOCoZbM GOqDM1yHMekHi9DzgmrHT09qA1XgJRO6FxDxwXeYActrd7kNWv8Q1hx9RXK5HEtoih5U De2XiVapKTEE1/mqOQyhOxz1HqSy4wTk7cFL8GsNz7SvAq9Gt/p6r5VT48H7MX6jnM5T nFNuSlRiTBVt00RUn0jOojEfoAVZb9Iir+J44k2dLfMShsUbZEYZqKL7O6wNy4gDpX7+ RuIkcej6iRBTOyid2U9GX+YgupX4EZO4TtJsF6FIb32i8A8ftSu5GmvUKirhJSAcm3vo qAmg== X-Gm-Message-State: APjAAAXklBueRn0YmySIFIL1nWe/bVSBG0oYWd52UWOEm5J+9w70sJPj /8R9QzUfG27yvqic0h09zws/Sw== X-Google-Smtp-Source: APXvYqxsot+KuzrRp/bZ42yX1xRSsmzeoxhjDbcJwWvURaSHFnyWN/tmsc5x4vnk1y4l48NbZvEEzw== X-Received: by 2002:a5e:d607:: with SMTP id w7mr3921189iom.237.1572011444742; Fri, 25 Oct 2019 06:50:44 -0700 (PDT) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id l21sm266655iok.87.2019.10.25.06.50.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Oct 2019 06:50:43 -0700 (PDT) Subject: Re: KASAN: null-ptr-deref Write in io_wq_cancel_all To: Dmitry Vyukov , syzbot Cc: linux-fsdevel , LKML , syzkaller-bugs , Al Viro References: <000000000000fbbe1e0595bac322@google.com> From: Jens Axboe Message-ID: <0e1b3410-95b0-f9d9-6838-486eae0bf5d7@kernel.dk> Date: Fri, 25 Oct 2019 07:50:42 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 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 10/25/19 5:58 AM, Dmitry Vyukov wrote: > On Fri, Oct 25, 2019 at 1:51 PM syzbot > wrote: >> >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: 139c2d13 Add linux-next specific files for 20191025 >> git tree: linux-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=17ab5a70e00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=28fd7a693df38d29 >> dashboard link: https://syzkaller.appspot.com/bug?extid=d958a65633ea70280b23 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> >> Unfortunately, I don't have any reproducer for this crash yet. >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+d958a65633ea70280b23@syzkaller.appspotmail.com > > +Jens Let me know if/when you have a reproducer for this one. I initially thought this was a basic NULL pointer check, but it doesn't look like it. I wonder if the thread handling the request got a signal, and since it had the task file_table with the io_uring fd attached, it's triggering an exit. I'll poke at it, but don't immediately see the issue. -- Jens Axboe