Bug#270561: xserver-xfree86: Fatal server error: Caught signal 11

["Kingsley G. Morse Jr." <change@nas.com>]

Hi Branden,

I hope this message finds you well.

Happy Holidays!

I have good news and bad news.

The good news is that X hasn't crashed on my box
for weeks.

The bad news is that I don't know why it was
crashing. 

My best guess is that switching from an OSS sound
driver to ALSA for a VT8233A audio chip solved the
problem, but frankly, I'm guessing.

It's OK with me if you close this bug report.

Keep up the good work,
Kingsley

On 10/18/04 04:53, Branden Robinson wrote:
> On Fri, Oct 15, 2004 at 03:44:42PM -0700, Kingsley G. Morse Jr. wrote:
> > Unfortunately, no.
> > 
> > In fact, X crashed most recently while I wasn't using it, so I'm unaware
> > of anything in particular to focus on.
> > 
> > However, I agree in principle with narrowing down the cause of the crash.
> > 
> > Can X be coaxed to elicit more verbose diagnostics, like a stack trace,
> > for example?
> 
> No; the log file is as verbose as the X server gets.
> 
> However, a backtrace can be coaxed out of the X server if you run the
> debugging version of the package and install GDB.
> 
> [The following is a form letter.]
> 
> Can you reproduce the problem with xserver-xfree86-dbg?  Install the
> package and tell debconf you want to use that X server.  Then restart the X
> server and try to reproduce the bug (should be easy).  If it doesn't crash,
> let us know.  If it does crash, become root, enable core dumps ("ulimit -c
> unlimited" in bash), start the X server as root and reproduce the crash
> again:
> 
> # startx $(which x-terminal-emulator) -- :1
> 
> (If no X server is running at DISPLAY=:0, you can leave off the "-- :1"
> part).
> 
> This will launch the X server running a lone terminal client with no window
> manager.  Run the client that provokes the crash from the terminal prompt.
> If the X server crashes, it should leave a core dump in /etc/X11.
> 
> We then run the GNU Debugger, GDB, on the core file and executable.  We're
> interested in a backtrace of execution.  The X server has a signal handler
> in it so it can do things like exit gracefully (restoring the text console,
> and so forth), so we're not actually interested in all the stack frames --
> just those "above" the signal handler.
> 
> Here's an example GDB session I logged after provoking an artificial server
> crash (with "kill -SEGV").
> 
>   % gdb $(which XFree86-debug) core
>   GNU gdb 6.1-debian
>   Copyright 2004 Free Software Foundation, Inc.
>   GDB is free software, covered by the GNU General Public License, and you are
>   welcome to change it and/or distribute copies of it under certain conditions.
>   Type "show copying" to see the conditions.
>   There is absolutely no warranty for GDB.  Type "show warranty" for details.
>   This GDB was configured as "i386-linux"...Using host libthread_db library "/lib/libthread_db.so.1".
> 
>   Core was generated by `/usr/X11R6/bin/X :1'.
>   Program terminated with signal 6, Aborted.
>   Reading symbols from /usr/lib/libfreetype.so.6...done.
>   Loaded symbols for /usr/lib/libfreetype.so.6
>   Reading symbols from /usr/lib/libz.so.1...done.
>   Loaded symbols for /usr/lib/libz.so.1
>   Reading symbols from /lib/libm.so.6...done.
>   Loaded symbols for /lib/libm.so.6
>   Reading symbols from /lib/libc.so.6...done.
>   Loaded symbols for /lib/libc.so.6
>   Reading symbols from /lib/ld-linux.so.2...done.
>   Loaded symbols for /lib/ld-linux.so.2
>   #0  0x400f2721 in kill () from /lib/libc.so.6
>   (gdb) bt
>   #0  0x400f2721 in kill () from /lib/libc.so.6
>   #1  0x400f24c5 in raise () from /lib/libc.so.6
>   #2  0x400f39e8 in abort () from /lib/libc.so.6
>   #3  0x08464b8c in ddxGiveUp () at xf86Init.c:1173
>   #4  0x08464c6b in AbortDDX () at xf86Init.c:1224
>   #5  0x08508bd7 in AbortServer () at utils.c:436
>   #6  0x0850a563 in FatalError (f=0x8a26ea0 "Caught signal %d.  Server aborting\n") at utils.c:1421
>   #7  0x0847fbf5 in xf86SigHandler (signo=11) at xf86Events.c:1198
>   #8  <signal handler called>
>   #9  0x40199dd2 in select () from /lib/libc.so.6
>   #10 0x401f8550 in ?? () from /lib/libc.so.6
>   #11 0x400164a0 in ?? () from /lib/ld-linux.so.2
>   #12 0xbffff8f0 in ?? ()
>   #13 0x08502520 in WaitForSomething (pClientsReady=0xbffff944) at WaitFor.c:350
>   #14 0x084cff54 in Dispatch () at dispatch.c:379
>   #15 0x084e763c in main (argc=2, argv=0xbffffe04, envp=0xbffffe10) at main.c:469
>   (gdb) bt full -7
>   #9  0x40199dd2 in select () from /lib/libc.so.6
>   No symbol table info available.
>   #10 0x401f8550 in ?? () from /lib/libc.so.6
>   No symbol table info available.
>   #11 0x400164a0 in ?? () from /lib/ld-linux.so.2
>   No symbol table info available.
>   #12 0xbffff8f0 in ?? ()
>   No symbol table info available.
>   #13 0x08502520 in WaitForSomething (pClientsReady=0xbffff944) at WaitFor.c:350
>           i = 2
>           waittime = {tv_sec = 118, tv_usec = 580000}
>           wt = (struct timeval *) 0xbffff910
>           timeout = 599999
>           standbyTimeout = 1199999
>           suspendTimeout = 1799999
>           offTimeout = 2399999
>           clientsReadable = {fds_bits = {0 <repeats 32 times>}}
>           clientsWritable = {fds_bits = {1, 146318192, -1073743800, 140704020, 147350456, 147350040, 2, 312, 1, 1075418973, -1073743800, 139461033, 147374816, 1, -1073743680, 9, 1073833120, -1073742332, 
>       -1073743784, 139526463, 9, -1073743680, 1, 139458611, 147350456, 147350040, -1073743752, 139529154, 147339744, -1073743680, 1, 1074655182}}
>           curclient = 147556952
>           selecterr = 3
>           nready = 0
>           devicesReadable = {fds_bits = {1, 1, 6, 146327832, 147350508, 0, 315, 302, 9, 3, 315, 302, 9, 3, 0, 0, 146318192, 1075807568, -1073743880, 137843170, 146125816, 3, 313, 147556952, 0, 15066597, 3, 
>       -1, 147350500, 1, 0, 146319268}}
>           now = 16069
>           someReady = 0
>   #14 0x084cff54 in Dispatch () at dispatch.c:379
>           clientReady = (int *) 0xbffff944
>           result = 0
>           client = 0x8c8c2e0
>           nready = -1
>           icheck = (HWEventQueuePtr *) 0x8b45c68
>           start_tick = 940
>   #15 0x084e763c in main (argc=2, argv=0xbffffe04, envp=0xbffffe10) at main.c:469
>           i = 1
>           j = 2
>           k = 2
>           error = -1073742332
>           xauthfile = 0xbfffffba "/root/.Xauthority"
>           alwaysCheckForInput = {0, 1}
>   (gdb) quit
> 
> In the example above, you can see I used "bt full -7" to get the
> "outermost" seven stack frames, complete with local variable information,
> where available.
> 
> If you could send us something smiliar, that would be very helpful.
> 
> -- 
> G. Branden Robinson                |    There is no housing shortage in
> Debian GNU/Linux                   |    Lincoln today -- just a rumor that
> branden@debian.org                 |    is put about by people who have
> http://people.debian.org/~branden/ |    nowhere to live.    -- G. L. Murfin