Bug#848960: xserver-xorg segfaults after starting afterstep
History of previous conversations with Emilio Pozuelo (accidentally not posted
to 848960@bugs.debian.org):
Fri, 23 Dec 2016 00:04:49 +0100
Emilio suggested to obtain a backtrace, using the info at
https://www.x.org/wiki/Development/Documentation/ServerDebugging/
Wed, 11 Jan 2017 13:30:05 +0100
Frank observed that xserver-xorg-core-dbg, suggested by the info at
the above URL, is not mentioned at https://packages.debian.org for
xserver-xorg-core 2:1.19.0-3
Wed, 11 Jan 2017 13:41:47 +0100
Emilio advised to look at
https://wiki.debian.org/AutomaticDebugPackages for links to more
recent debug packages.
Based on what I found at that wiki I added
deb http://debug.mirrors.debian.org/debian-debug/ testing-debug main
to /etc/apt/sources.list and installed
xserver-xorg-core-dbgsym, xserver-xorg-video-ati-dbg (and by implication
xserver-xorg-video-radeon-dbg), and xserver-xorg-video-nouveau-dbg.
I'm afraid that what follows ends in something like an anti-climax, but here
we go:
Next I started the debug session. Here's the transcript:
GNU gdb (Debian 7.12-4) 7.12
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License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
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"/usr/bin/Xorg": not in executable format: File format not recognized
Attaching to process 8247
[New LWP 8251]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007fe479ae2fd3 in epoll_wait () at ../sysdeps/unix/syscall-template.S:84
84 ../sysdeps/unix/syscall-template.S: No such file or directory.
(gdb) cont
Continuing.
Thread 1 "Xorg" received signal SIGHUP, Hangup. [ I ended the session ]
0x00007fe479ae2fd3 in epoll_wait () at ../sysdeps/unix/syscall-template.S:84
84 in ../sysdeps/unix/syscall-template.S
(gdb) cont
Continuing.
[Thread 0x7fe46e0a8700 (LWP 8251) exited] [ I completed the logout ]
[New Thread 0x7fe46e0a8700 (LWP 12395)]
quit
^C
Thread 1 "Xorg" received signal SIGINT, Interrupt.
0x00007fe479ae2fd3 in epoll_wait () at ../sysdeps/unix/syscall-template.S:84
84 in ../sysdeps/unix/syscall-template.S
(gdb) detach
Detaching from program: /usr/lib/xorg/Xorg, process 8247
(gdb) quit
This time all actions successfully completed. No crash occurred. After killing
xdm and Xorg and restarting xdm the session didn't crash. I tried that several
times in a row, and all sessions ran OK.
Next, I deinstalled xserver-xorg-core-dbgsym and restarted xdm/Xorg
The session ran OK: no crashes.
Then I deinstalled xserver-xorg-video-ati-dbg (and by implication
xserver-xorg-video-radeon-dbg) and restarted xdm/Xorg
Once again: the session ran OK, no crashes.
The only dbg package now left is xserver-xorg-video-nouveau-dbg. I deinstalled
it and restarted xdm/Xorg
Contrary to my expectations, this session ran OK as well.
As a final test I rebooted my computer. After the reboot I opened another X
session using afterstep and no problems were encountered.
So, I have absolutely no idea what caused the crashes I experienced in
December, and neither do I know why no crashes occurred when using fvwm as
window manager.
But since the problem doesn't manifest itself anymore, there's clearly no way
to debug it and consequently I suggest to end this bug report.
Emilio, thank you for your cooperation, so far.
--
Frank B. Brokken
Center for Information Technology, University of Groningen
(+31) 50 363 9281
Public PGP key: http://pgp.surfnet.nl
Key Fingerprint: DF32 13DE B156 7732 E65E 3B4D 7DB2 A8BE EAE4 D8AA
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