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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH, USER_AGENT_MUTT autolearn=unavailable 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 3F5B8C4321B for ; Mon, 10 Jun 2019 18:19:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1A83520862 for ; Mon, 10 Jun 2019 18:19:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560190752; bh=4fWiZZz2M6eGYS+d2dn1LzySa5nwwCMieUm3XeFYJpQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=rqHRE4I9tdVYMUdux8jlgjEo+8bzWh5L4l+LZpr9HzFxU7QY4m0zOjYOpgniTUbyX 8wT3nht+hUdtgEL1s7baboYzHdk9zZNqNdEvASTlx5YinnLx+kfFSHNzP6fXL3eq4v HOjBQPIysKrX7w/cwgkLAmDznY4UHxQ52r7zDxvk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728582AbfFJSTH (ORCPT ); Mon, 10 Jun 2019 14:19:07 -0400 Received: from mail-ua1-f43.google.com ([209.85.222.43]:34690 "EHLO mail-ua1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726214AbfFJSTG (ORCPT ); Mon, 10 Jun 2019 14:19:06 -0400 Received: by mail-ua1-f43.google.com with SMTP id 7so3450214uah.1; Mon, 10 Jun 2019 11:19:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Rd7jWnbbAp4RfevQw78c7K7px6JtJUHSgmHkrc6gVU4=; b=NoqhzsNrSi7dYNU8yAmO1tRvsVK2jYNpAak6UvyF+UpISCg7sKKp+j/LODUeyNnGGM hB7/cEOSqt99ksyAvEbmXLwW8gjf7zgNTpXKPcsWgHJE4LXlXBTkZJGO863W9xk+Vfat bVgUYj+I5DTk0xpfsYwKEFMzHbBQ25NIZlsNGltPdj8av7Iu80Z3ZEndzt9anwoXuCJg w9DHDLsr4c9Shkn8cu5DWwZD9OGLwo8vPBxuBGW+Dso5njoo8SXGL4M9eyzxFV0sZd+c pIqDtQM6P93Q2vkFkzEs75Hx4V++tpJfhxoXy6X8hAERs+zTcnH3Ww+l4K093n0sdlZm G5qA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=Rd7jWnbbAp4RfevQw78c7K7px6JtJUHSgmHkrc6gVU4=; b=kAe/cL6qFoeAr8n1bnqFNTGbwblwVe3x+CaD0KysG7ckp0vKTlCG8LqnU9leE4aHpM WGz54vrpPqM/INDqBNcIhLuX+4yrt7pcE+VE1Xz7p5ZHhIfyqT4+FlM+WV6epUh8p8qV qb6MYibGtMNTvwJ+Iifn1vb7NT8BLr6hzhUt18f+gW+EYNVgszOhJgFG4ubj8FkSnNPV Z9sOJjjyfsUwL4AfTgnAw2P3WG88UrVPudwmud+8/i6NCZW1dfDsCAO2I1K77oGCUrMY r6PkOVB8s4fP5y7k7DHYHOabkMwKLTCMvNAhDELDTP1xewavc1uUzv8OxuEekJ48YzC9 jWFA== X-Gm-Message-State: APjAAAXfPdG0CQk3CYTYuc2AgFHglUzTMdtRRurxrElUFHt8Tm4hF3WQ uXJ1MY5dO7sgVOF2QCGJ/2Y= X-Google-Smtp-Source: APXvYqyQrkANAPukJc9v5IcPa2tL2EIoyvjbdXZpPEWyXnxL8ESjiYbyJ4IvKpakUqHqBNPtNUcbQw== X-Received: by 2002:ab0:60c4:: with SMTP id g4mr8141145uam.46.1560190745317; Mon, 10 Jun 2019 11:19:05 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::2:1677]) by smtp.gmail.com with ESMTPSA id t20sm4657335vkd.53.2019.06.10.11.19.03 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Jun 2019 11:19:04 -0700 (PDT) Date: Mon, 10 Jun 2019 11:19:01 -0700 From: Tejun Heo To: Hillf Danton Cc: syzbot , ast@kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, daniel@iogearbox.net, hannes@cmpxchg.org, kafai@fb.com, linux-kernel@vger.kernel.org, lizefan@huawei.com, netdev@vger.kernel.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, yhs@fb.com Subject: Re: KASAN: null-ptr-deref Read in css_task_iter_advance Message-ID: <20190610181901.GC3341036@devbig004.ftw2.facebook.com> References: <00000000000055aba7058af4d378@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00000000000055aba7058af4d378@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hello, Hillf. On Tue, Jun 11, 2019 at 12:59:23AM +0800, Hillf Danton wrote: > >syzbot will keep track of this bug report. See: > >https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > > Ignore my noise if you have no interest seeing the syzbot report. They're awesome. > The following tiny diff, made in the hope that it may help you perhaps > reproduce the crash, waits css lock holders and then pick task off > the list of dying tasks. I already posted a fix. Well, at least I think it's the fix. https://www.spinics.net/lists/cgroups/msg22468.html Thanks. -- tejun