From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Mathias Koehrer" Subject: Re: BUG: unable to handle kernel NULL pointer dereference on 3.18.13-rt10 Date: Tue, 14 Jul 2015 16:24:54 +0200 Message-ID: <55A51BB6.4070606@etas.com> References: <453aa7881ded41e7a843795863ac1712@FE-MBX1012.de.bosch.com> <20150710132318.GA27402@linutronix.de> <3c9ae4a1f9cb4ac3a96a28c3f65f9442@FE-MBX1012.de.bosch.com> <20150713091237.GA31747@linutronix.de> <20150713113430.4c18c965@gandalf.local.home> <523c30ce4e4c4b53befcd288db178db9@FE-MBX1012.de.bosch.com> <20150714101551.2f39f196@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Cc: Sebastian Andrzej Siewior , Thomas Gleixner , "linux-rt-users@vger.kernel.org" To: Steven Rostedt Return-path: Received: from smtp6-v.fe.bosch.de ([139.15.237.11]:65228 "EHLO smtp6-v.fe.bosch.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751777AbbGNOY5 (ORCPT ); Tue, 14 Jul 2015 10:24:57 -0400 In-Reply-To: <20150714101551.2f39f196@gandalf.local.home> Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hi Steve! >>> What's the test that was run, and how did it enable function tracing? >> >> The tracing was enabled within an init script using the following bash commands: >> if ! grep -q "/sys/kernel/debug" /proc/mounts; then >> mount -t debugfs nodev /sys/kernel/debug >> fi >> if [ -d /sys/kernel/debug/tracing ]; then >> ( >> cd /sys/kernel/debug/tracing >> echo "function" > current_tracer >> echo "1" > tracing_on >> >> echo "1" > /proc/sys/kernel/ftrace_dump_on_oops >> ) >> fi >> >> >> The test was to reboot the PC permanently (every minute). >> The reboot has been initiated by another PC that remotely controls the PC under test. >> > > How reproducible is this? Unfortunately this is not really reproducable. I caught this bug after approx. 400 reboots while hunting another bug... Regards Mathias