Re: how debug DOSEMU crash?

[Frantisek Hanzlik <franta@hanzlici.cz>]

Frantisek Hanzlik wrote:
> Frantisek Hanzlik wrote:
>> ...
> 
> Weird... When I run:
> 
> gdb /usr/bin/dosemu.bin
> (gdb) run -X -p
> 
> (which perhaps is same as start with (x)dosemu script), then DOSEMU
> is not crashing and I can enter commands to its FreeDOS and all seems
> works fine. But running without gdb ends with crash as described
> in previous email.
> 
> Isn't it some other sort of not long ago tackled problem in thread
> "dosemu-1.4.0-11.2053svn on Fedora 15 x86 won't start"?
> 
> How now? I have installed debuginfo file (see below), should I start
> learning gdb or can anyone give quick touch in right direction?

I tried run dosemu, and when it stay on dos prompt I connect to it
with gdb with Program_Path Program_PID :

$ gdb /usr/bin/dosemu.bin 24635
GNU gdb (GDB) Fedora (7.2-52.fc14)
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/bin/dosemu.bin...Reading symbols from /usr/lib/debug/usr/bin/dosemu.bin.debug...done.
done.
Attaching to program: /usr/bin/dosemu.bin, process 24635
Reading symbols from /usr/lib/libvga.so.1...Reading symbols from
/usr/lib/debug/usr/lib/libvga.so.1.9.25.debug...done.
done.
Loaded symbols for /usr/lib/libvga.so.1
Reading symbols from /lib/librt.so.1...Reading symbols from /usr/lib/debug/lib/librt-2.13.so.debug...done.
done.
Loaded symbols for /lib/librt.so.1
Reading symbols from /lib/libdl.so.2...Reading symbols from /usr/lib/debug/lib/libdl-2.13.so.debug...done.
done.
Loaded symbols for /lib/libdl.so.2
Reading symbols from /lib/libm.so.6...Reading symbols from /usr/lib/debug/lib/libm-2.13.so.debug...done.
done.
Loaded symbols for /lib/libm.so.6
Reading symbols from /lib/libgcc_s.so.1...Reading symbols from
/usr/lib/debug/lib/libgcc_s-4.5.1-20100924.so.1.debug...done.
done.
Loaded symbols for /lib/libgcc_s.so.1
Reading symbols from /lib/libc.so.6...Reading symbols from /usr/lib/debug/lib/libc-2.13.so.debug...done.
done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/libpthread.so.0...Reading symbols from
/usr/lib/debug/lib/libpthread-2.13.so.debug...done.
[Thread debugging using libthread_db enabled]
done.
Loaded symbols for /lib/libpthread.so.0
Reading symbols from /lib/ld-linux.so.2...Reading symbols from /usr/lib/debug/lib/ld-2.13.so.debug...done.
done.
Loaded symbols for /lib/ld-linux.so.2
Reading symbols from /usr/lib/dosemu/libplugin_X.so...done.
Loaded symbols for /usr/lib/dosemu/libplugin_X.so
Reading symbols from /usr/lib/libXxf86vm.so.1...Reading symbols from
/usr/lib/debug/usr/lib/libXxf86vm.so.1.0.0.debug...done.
done.
Loaded symbols for /usr/lib/libXxf86vm.so.1
Reading symbols from /usr/lib/libXext.so.6...Reading symbols from
/usr/lib/debug/usr/lib/libXext.so.6.4.0.debug...done.
done.
Loaded symbols for /usr/lib/libXext.so.6
Reading symbols from /usr/lib/libX11.so.6...Reading symbols from
/usr/lib/debug/usr/lib/libX11.so.6.3.0.debug...done.
done.
Loaded symbols for /usr/lib/libX11.so.6
Reading symbols from /usr/lib/libxcb.so.1...Reading symbols from
/usr/lib/debug/usr/lib/libxcb.so.1.1.0.debug...done.
done.
Loaded symbols for /usr/lib/libxcb.so.1
Reading symbols from /usr/lib/libXau.so.6...Reading symbols from
/usr/lib/debug/usr/lib/libXau.so.6.0.0.debug...done.
done.
Loaded symbols for /usr/lib/libXau.so.6
Reading symbols from /lib/libnss_files.so.2...Reading symbols from
/usr/lib/debug/lib/libnss_files-2.13.so.debug...done.
done.
Loaded symbols for /lib/libnss_files.so.2
Reading symbols from /usr/lib/libXcursor.so.1...Reading symbols from
/usr/lib/debug/usr/lib/libXcursor.so.1.0.2.debug...done.
done.
Loaded symbols for /usr/lib/libXcursor.so.1
Reading symbols from /usr/lib/libXrender.so.1...Reading symbols from
/usr/lib/debug/usr/lib/libXrender.so.1.3.0.debug...done.
done.
Loaded symbols for /usr/lib/libXrender.so.1
Reading symbols from /usr/lib/libXfixes.so.3...Reading symbols from
/usr/lib/debug/usr/lib/libXfixes.so.3.1.0.debug...done.
done.
Loaded symbols for /usr/lib/libXfixes.so.3
0x005bf424 in __kernel_vsyscall ()
(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x00c057da in do_lookup_x (new_hash=165829478, old_hash=0xbfa985f4, ref=0xa654ec, result=0xbfa985e8,
scope=0xc1aa5c,
    i=5, flags=1, skip=0x0, undef_map=0x9037970) at dl-lookup.c:248
248			    if (((*hasharr ^ new_hash) >> 1) == 0)
(gdb) bt
#0  0x00c057da in do_lookup_x (new_hash=165829478, old_hash=0xbfa985f4, ref=0xa654ec, result=0xbfa985e8,
    scope=0xc1aa5c, i=5, flags=1, skip=0x0, undef_map=0x9037970) at dl-lookup.c:248
#1  0x00c05a41 in _dl_lookup_symbol_x (undef_name=0xa66aa2 "XkbLookupKeySym", undef_map=0x9037970,
ref=0xbfa98630,
    symbol_scope=0x9037b28, version=0x0, type_class=1, flags=1, skip_map=0x0) at dl-lookup.c:736
#2  0x00c09da7 in _dl_fixup (l=<value optimized out>, reloc_arg=<value optimized out>) at dl-runtime.c:118
#3  0x00c10420 in _dl_runtime_resolve () at ../sysdeps/i386/dl-trampoline.S:37
#4  0x00a6ee29 in map_X_event (display=0x9039b10, e=0xbfa987ec, result=0xbfa986e4) at keyb_X.c:287
#5  0x00a6f4ea in X_keycode_process_key (e=0xbfa987ec) at keyb_X_keycode.c:602
#6  0x00a6eef8 in X_process_key (e=0xbfa987ec) at keyb_X.c:313
#7  0x00a6cfc7 in X_handle_events () at X.c:1558
#8  0x0808c364 in SIGALRM_call () at signal.c:777
#9  0x0808c1b0 in handle_signals_force (force_reentry=<value optimized out>) at signal.c:650
#10 0x0808964d in do_periodic_stuff () at int.c:2290
#11 0x080a8f4c in run_vm86 () at do_vm86.c:426
#12 0x080a930c in loopstep_run_vm86 () at do_vm86.c:446
#13 0x0805e295 in main (argc=3, argv=0xbfaa8b44) at emu.c:453
(gdb)


When touching keyboard, dosemu crashed again as before. Above is gdb printout
and backtrace.
But now I'm perhaps definitively out. dl-lookup.c seems be some glibc routine.
This is problem for _real_ programmer.

Franta Hanzlik