Path: csiph.com!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod From: Tejun Heo Newsgroups: linux.kernel Subject: Re: NULL pointer dereference in cgroup Date: Mon, 13 Mar 2017 18:10:03 +0100 Message-ID: References: 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=Ns3+As1/hCmKEgjfAsu58l4PRa6j1/Ubey+PSQXD07s=; b=MRN8+J9g7n5tdNrxeIbcrqPL2WmLQC+ICMU3Jod7Ri0WpC0BuxK/Fr872UtaFD7k/j wThuc4hZ/3FJTaSWLIjyRInIIW+5gVs1uv7EA1u+Cl5YjP+yw4iZLhFsTvzpj1wugHph 6uf01U/4C0cnFh2PF4Kr4S6voJZzi3lfqgacLuNnmqNAp8N7jCuDTMX6RS3G3iY7bQzc /ej4diMXfUHriThHAD2Ofua07iTvLE9slvkPOkaPXgsAEOsUURstGkt9iFsfkEKebwZh LcOwmQaYKIWyaqvud1gV485xjEfjyTwET4/dmqREwMzb+jskiGM/d2A7llMX2XOdytIR 4FZw== 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=Ns3+As1/hCmKEgjfAsu58l4PRa6j1/Ubey+PSQXD07s=; b=TyQmxKc6FT9Io0MtWX+I0pXwGCKtVn6+NY5CjfhDfIFPvnRnUcEhvaSmjofgyCGwGd GvxZnsgEyUuBkXA7Oen7xuRMABDDbXlpKHZOIzqtBUb9uVfs3nJMxdsiS3jHK7dFuq8a udvHVWIKTQ6/iRP/JXooTQenJj3YTre77nkCYjvxBnszY7NTJf4YOSgH244odp5YWV8x kHbIqYq7IkYdtYos6yzj2y9uVzB2Iv07lEM0AjeXYyaWh5PGumQ7EunAqZqb1aMOmpEZ +rvCdYy9Idp27TgBi54atDu5q8b8EyH9u2io/wx26iqY9ViPYF0TjZTwGGRNn28v3YBr zV+g== X-Gm-Message-State: AMke39l76QefDbvbSAm4kCQq8W31FBdUEU7KdO+tSisjQpcT8CaEsuKK1UQwX/5OTHsBKw== X-Received: by 10.129.91.194 with SMTP id p185mr18016604ywb.50.1489424700884; Mon, 13 Mar 2017 10:05:00 -0700 (PDT) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.7.1 (2016-10-04) Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 23 Organization: linux.* mail to news gateway X-Original-Cc: Zefan Li , "Eric W. Biederman" , Johannes Weiner , Andrew Morton , linux-kernel@vger.kernel.org X-Original-Date: Mon, 13 Mar 2017 13:04:59 -0400 X-Original-Message-ID: <20170313170459.GA15709@htj.duckdns.org> X-Original-References: <20170308184616.553hndqxd7lljqkq@charon> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1599639 Hello, On Wed, Mar 08, 2017 at 06:46:16PM +0000, Luis Henriques wrote: > Hi, > > I've seen this only once, and can't reproduce it. But here it is anyway: > > https://postimg.org/image/pn94k1yov > > (Not sure png files are accepted on LKML.) > > This occurred in a VM while booting 4.11.0-rc1 It was trying to migrate a process and encountered a NULL deref while trying to find the destination css_set. Unfortunately, it's difficult to tell what went wrong with just the posted backtrace. If you built the kernel with debuginfo, the output of addr2line could help quite a bit. Thanks. -- tejun