From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bernard Pidoux Subject: Re: CPU: 0 Not tainted (3.1.9+ #1) when ifconfig rose0 down Date: Tue, 31 Jul 2012 17:27:39 +0200 Message-ID: <5017F96B.1060701@free.fr> References: <5017E786.5000102@free.fr> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5017E786.5000102@free.fr> Sender: linux-hams-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-hams , Linux Netdev List Here is a complementary observation. Trying to remove rose module with rmmod rose did not create any kernel panic. However, there is an endless message from the kernel saying : Message from syslogd@raspberrypi at Jul 31 17:22:40 ... kernel:[ 831.579007] unregister_netdevice: waiting for rose0 to become free. Usage count = 23 Message from syslogd@raspberrypi at Jul 31 17:22:50 ... kernel:[ 841.739390] unregister_netdevice: waiting for rose0 to become free. Usage count = 23 Message from syslogd@raspberrypi at Jul 31 17:23:00 ... kernel:[ 851.899758] unregister_netdevice: waiting for rose0 to become free. Usage count = 23 ..... As observed at many occasions, count number seems to be random ! and the same message keeps going without any change of count number. At the same time, there is no possibility to recover the command line on any console. However I could loggin via ssh and I noticed that rose0 device is actually no more in the ifconfig list. If I try to remove rose with rmmod rose I get : root@raspberrypi:/home/pi# rmmod rose libkmod: ERROR ../libkmod/libkmod-module.c:753 kmod_module_remove_module: could not remove 'rose': Device or resource busy Error: could not remove module rose: Device or resource busy Does this help ? On 31/07/2012 16:11, Bernard Pidoux wrote: > Hi, > > I observe systematically a kernel panic when I try to shutdown rose0 > device using ifconfig rose0 down > > This is happening on two very different ROSE implementation, one is on a > machine with x86-64 kernel 4.6.3 on an Intel core 2 duo CPU > the other is on a RaspBerry Pi with Raspbian and 3.1.9+ wheezy kernel > recompiled with AX.25 modules (ax25, rose, netrom, 6pack, kiss) enabled. > > Here is an image of the screen dump : > > http://f6bvp.org/photos/rose_device_event.JPG > > It can be noticed that PC is at rose_device_event and > LR is at sock_def_wakeup > > One thing to be noticed is that when I close before all ROSE and AX.25 > applications, there are still a few populated sockets, probably for one > of the program did not close the sockets properly. > > I that case, does rose module should accept to shutdown rose0 device ? > However, I guess that it should not create a kernel panic due to a > kernel NULL pointer. > > I don't know what to do in order to debug that issue. > > Bernard >