From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753440AbaCaQcc (ORCPT ); Mon, 31 Mar 2014 12:32:32 -0400 Received: from www.linutronix.de ([62.245.132.108]:34531 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751719AbaCaQcb (ORCPT ); Mon, 31 Mar 2014 12:32:31 -0400 Date: Mon, 31 Mar 2014 18:32:40 +0200 (CEST) From: Thomas Gleixner To: Vince Weaver cc: LKML , Peter Zijlstra , Ingo Molnar , Steven Rostedt Subject: Re: perf_fuzzer: BUG in kfree() in ftrace_graph_exit_task In-Reply-To: Message-ID: References: User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 31 Mar 2014, Vince Weaver wrote: > > This turned up with the perf_fuzzer, haswell, 3.14. > > I'm not sure if this is related to the other object corruption bug I am > seeing. The sympstoms are similar (BUG when dereferencing low invalid > kernel address) but this time the hrtimer code is not involved at all. > > This isn't reproducible, that is if I re-run the fuzzer with the same > random seed after reboot the bug doesn't trigger. > > > [ 5498.573458] BUG: unable to handle kernel NULL pointer dereference at 000000000000006c > [ 5498.585181] IP: [] kfree+0x91/0x220 > [ 5498.593887] PGD 0 > [ 5498.599365] Oops: 0000 [#1] SMP > [ 5498.606127] Dumping ftrace buffer: > [ 5498.612973] (ftrace buffer empty) > [ 5498.619868] Modules linked in: nfsd auth_rpcgss ..... > [ 5498.720303] CPU: 1 PID: 13 Comm: ksoftirqd/1 Tainted: G W 3.14.0+ #14 It's already tainted with W, so there was a warning before that crash. It would be interesting to see that as well. Thanks, tglx