How To Use GDB for your game.core for Debug

[YukiPowa 5]

Hello!

I've never seen the above tutorial, yet useful!
Full application server administrator for help when they have a game.core without doubt that the answer is and precisely.

So here, the very easy, the command to type is: gdb.

 

Exemple : gdb /usr/metin2/share/game /usr/metin2/channel1/game.core

 

This command will tell you where does the error through the .core.
Or at least it will help you to know or just the problem.

 

IMPORTANT: You must not have a game to strip debug!

 

Good bye

 

[Alina 228]

Thank you very much for sharing!

 

You can also run the gamefile with gdb.

This all requires that you're building your gamefile with debug support of course Otherwise backtracing can produce bad results.

 

gdb game

run

 

Then you can reproduce the bug and see what happens. gdb can help a lot when fixing game crashes

[Ken 891]

Thank you very much for sharing!

 

You can also run the gamefile with gdb.

This all requires that you're building your gamefile with debug support of course Otherwise backtracing can produce bad results.

 

gdb game

run

 

Then you can reproduce the bug and see what happens. gdb can help a lot when fixing game crashes

 

Extra information ;

When your program is run via gdb and system give crash, gdb is stopped and show the line..

 

Kind Regards

Ken

[Remix 45]

You don't have to run the game in gdb again.

Just backtrace it.

[Night 363]

you can backtrace it using   : bt

for full backtrace use :

bt full

[Mashkin 16]

You should note that FreeBSD is not really good with cross-platform compiling/debugging.

Since game files are usually compiled for x86 (32bit), debugging on an x86-64 machine is quite hard.

 

I usually use an x86 VM or server for debugging instead of messing with this issue.

[Ira™ 41]

What are you talking here, this is not any tutorial.

What you say is only 30% as game.core analyzes. There is nothing, that do bt full.

 

Carry On.

[Remix 45]

Since game files are usually compiled for x84 (32bit), debugging on an x86-64 machine is quite hard.

 

That's why you should always use a 32bit OS to debug it.

[Think 117]

You should note that FreeBSD is not really good with cross-platform compiling/debugging.

Since game files are usually compiled for x84 (32bit), debugging on an x86-64 machine is quite hard.

 

I usually use an x86 VM or server for debugging instead of messing with this issue.

Interestingly we debug perfectly on a 64bit machine having a 32bit game compiled.

[Cataclismo 86]

I am building my game file using -g flag, but when I am trying to run the game using gdb I get the message: no debugging symbols found.

Also, if I am trying to use game.core it says that this file does not exists.

I am building the game under 32-bit machine and running it on a 64-bit machine. I don't have -s flag.

[.Devil. 28]

I am building my game file using -g flag, but when I am trying to run the game using gdb I get the message: no debugging symbols found.

Also, if I am trying to use game.core it says that this file does not exists.

I am building the game under 32-bit machine and running it on a 64-bit machine. I don't have -s flag.

You need to read the core as i386 (x86). You can use:

set gnutarget i386-marcel-freebsd
file game
core game.core
[...]

[Cataclismo 86]

 

I am building my game file using -g flag, but when I am trying to run the game using gdb I get the message: no debugging symbols found.

Also, if I am trying to use game.core it says that this file does not exists.

I am building the game under 32-bit machine and running it on a 64-bit machine. I don't have -s flag.

You need to read the core as i386 (x86). You can use:

set gnutarget i386-marcel-freebsd
file game
core game.core
[...]

 

I've tried under the same machine where I compiled the core and I got same messages.

[Thavo 4]

"/usr/mt2/game99/game.core" is not a core dump: File format is ambiguous"

How do I fix it?

[YukiPowa 5]

Your machine virtual is x64 ?

 

Use x86

[Night 363]

if you use a x64 machine do this :

# gdb
(gdb) set gnutarget i386-marcel-freebsd

(gdb) file game
(gdb) core game.core
(gdb) bt full

(gdb) quit
#

PS : use

bt

to get a small amount of info (a summery) it can as well be help full with some info like the time in both syserr and syslog can pretty much clear your bug or give you a general idea about it.

edit :

thx to martysama0134

[RatCatcher 77]

Extra information ;

When your program is run via gdb and system give crash, gdb is stopped and show the line..

 

Kind Regards

Ken

Isn't that totally obvious since we're talking about debugging? [likehunting intensifies]

[Thavo 4]

Your machine virtual is x64 ?

 

Use x86

 

Thanks for answer, there's no other way to use in 64 bits?

[Night 363]

 

Your machine virtual is x64 ?

 

Use x86

 

Thanks for answer, there's no other way to use in 64 bits?

 

look at my last post

[Thavo 4]

 

 

Your machine virtual is x64 ?

 

Use x86

 

Thanks for answer, there's no other way to use in 64 bits?

 

look at my last post

 

 

When I write :

file /usr/server/share/bin/game it shows me the following error 

Reading symbols from /usr/server/share/bin/game...Dwarf Error: wrong version in compilation unit header (is 4, should be 2) 

 

[Benhero 23]

Hey Everyone.

I have a question. What is now the best way to debug a game crash?

I want to debug it on a 64 Bit System...

I Try gdb but it not work.

Follow error appears:

GNU gdb 6.1.1 [FreeBSD]
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 "amd64-marcel-freebsd"...Dwarf Error: wrong version in compilation unit header (is 4, should be 2) [in module /usr/games/channel1/channel1_1/game1_1]

Thanks for any help!

[wezt 94]

Hi, try to update gdb for last version 

pkg install gdb-7.9.1

and run it like

/usr/local/bin/gdb791

 

[Benhero 23]

i already update gdb and to run it like this dont work :/

Greatz

[wezt 94]

Would be nice to see errors which you get with new gdb. If it's the same, then try to compile the game without -O -O2 -O3 flags and with -g flag (you need to check each Makefile).

Furthermore I can advice you to make cmd file for gdb and start it with -x argument, gdb.cmd file should contains path to directories with source files, it will help to see  c++ code while debugging.

Example of my gdb.cmd

directory /root/workspace/mainline/extern/include/boost
directory /root/workspace/mainline/extern/include
directory /root/workspace/mainline/extern/lib
directory /root/workspace/mainline/src_gcc49/libdevil
directory /root/workspace/mainline/src_gcc49/liblua/include
directory /root/workspace/mainline/src_gcc49/libthecore/lib
directory /root/workspace/mainline/src_gcc49/libpoly
directory /root/workspace/mainline/src_gcc49/libsql
directory /root/workspace/mainline/src_gcc49/libgame/lib
directory /root/workspace/mainline/src_gcc49/liblua/lib
directory /root/workspace/mainline/src_gcc49/game/src
directory /root/workspace/mainline/src_gcc49/db/src

So after you can start gdb like this:

/usr/local/bin/gdb791 -x gdb.cmd

 

Also, as it was told before, do not forget set target architecture (set gnutarget i386-marcel-freebsd in case if binary is 32bit one)

Edited June 30, 2015 by wezt

[Fr3zy94 59]

"/usr/home/game/channels/game99/core2/game.core" is not a core dump: File format is ambiguous

how i fix this?

[Benhero 23]

Don't use Stipped gamefile...

@wezt don't can make a gdb.cmd because server run on 64Bit system and i compile on a 32Bit system.. don't know how to compile on 64 bit <.< so i can't link source..

 

But the "/usr/local/bin/gdb7x1" works very well!

 

Thaks

Edited July 1, 2015 by Benhero