[MPlayer-users] Crash when dumping pcm with -ss (start position)

[The Wanderer]

Sebastian Kemper wrote:

> On Tue, Sep 25, 2007 at 06:15:53PM +0200, Reimar Doeffinger wrote:
> 
>>> I haven't got this gdb stuff figured out because the guide at 
>>> http://www.mplayerhq.hu/DOCS/HTML/en/bugreports_what.html#bugreports_core
>>> doesn't (yet) work for me.
>> 
>> Please explain your problems with it and help us improve it then.
> 
> Hello Reimar,
> 
> thank you for taking interest. OK, I'm aiming at producing the
> mplayer.bug file with all the relevant gdb output of the crash as
> described in the mplayer docs.
> 
> So I create a command file holding these lines:
> 
> bt
> disass $pc-32 $pc+32
> info all-registers
> 
> Then I run:
> 
> gdb /usr/bin/mplayer --core=core -batch --command=command_file >
> mplayer.bug
> 
> But all I get is this:
> 
> /home/sk/film/core: No such file or directory.
> No stack.
> /home/sk/film/command_file:2: Error in sourced command file:
> No registers.
> 
> This happens with mplayer SVN compiled a minute ago and gdb 6.6
> (stock Gentoo x86 gdb). I still have the first gdb command running,
> but it doesn't create a "core" file if thati's what the second gdb
> command is looking for.

The 'core' file would, as far as I have ever been able to tell, be
created (by the kernel?) when the crash happens, with the message "Core
dumped". If one was not created (and I have never seen one), then you
should not be reading the "core dump" part of the bug-reporting docs;
instead of using a nonexistent core file you will need to run the
crashing command from inside of gdb itself, then after it crashes issue
the suggested commands by hand.

IOW:

==
username:~$ gdb /usr/bin/mplayer
GNU gdb <version>
Copyright (C) 2006 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.
(gdb) run crashing-file -options-which-help-it-crash

...<let it run until it crashes>...

(gdb) bt

<it will print the backtrace>

(gdb) disass $pc-32 $pc+32

<it will print the disassembly>

(gdb) info all-registers

<it will print the registers>
==

Does that work any better?

-- 
       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.