[systemd-devel] Clarification around a segmentation fault from an udevd worker

[Lennart Poettering]

On Sat, 25.07.15 18:11, SF Markus Elfring (elfring at users.sourceforge.net) wrote:

> Hello,
> 
> I would like to clarify the setting of device file permissions
> for my needs.
> 
> So I extended the debug output at some source code places to see
> also better which lines are executed during my tests.
> I built these extensions for calls of the function "log_debug"
> on the current source files (last commit: 3460810e8c61986a4605ad80c9e4805eb95cb5a1)
> with the software "GCC 5.2.0" on my openSUSE Tumbleweed system.
> 
> I am experimenting a bit with this fresh server program.
> 
> Sonne:~ # systemctl stop systemd-udevd.service systemd-udevd-kernel.socket systemd-udevd-control.socket && /home/elfring/Projekte/Bau/systemd/systemd-udevd --debug
> 
> 
> Now I wonder about an error message like the following.
> 
> …
> adding watch on '/dev/dm-0'
> …
> seq 2633 forked new worker [19879]
> seq 2633 running
> IMPORT builtin 'usb_id' /usr/lib/udev/rules.d/40-libgphoto2.rules:9
> unable to access usb_interface device of '/sys/devices/pci0000:00/0000:00:02.0/usb3/3-2/3-2:1.0'
> IMPORT builtin 'usb_id' returned non-zero
> IMPORT builtin 'hwdb' /usr/lib/udev/rules.d/50-udev-default.rules:11
> worker [19879] terminated by signal 11 (Segmentation fault)
> worker [19879] failed while handling '/devices/pci0000:00/0000:00:02.0/usb3/3-2/3-2:1.0'
> …
> 
> I would appreciate your advices.
> 
> I hope that I do not need to extend all log messages with additional
> information details.
> It would be nice if I could find the failure place easier within
> a session with the help of a graphical debugger, wouldn't it?

This should usually generate a coredump. Depending on the distro and
its setup that coredump went to different places. Please ask your
distro for help how to acquire it. If you have it, please use "gdb" to
generate a stacktrace from it and provide it here.

Thanks,

Lennart

-- 
Lennart Poettering, Red Hat