Hi all,

I have a problem with debugger, I don't know if it is a my specific issue, but simply opening Lazarus and hitting F9 to compile and run an empty project, I get a "External: SIGSEGV" error. But only if I have gdb.exe as debugger. If I remove it from options, the project works.

Anyway... I can't understand if an issue that I have with a project where I'm working on, is a Lazarus issue or a my bug: sometime it works, sometime not. Randomly calling a function, it works, sometime not... so enabling debugging function, I wanted to see where was the problem... but I discovered that gdb.exe doesn't works anymore, with empty project also.

From here the question: it is only a my problem? Is gdb.exe working

and is there a real problem with lazarus/fpc?

I'm on Lazarus 0.9.30 r30385M FPC 2.4.2 i386-win32-win32/win64 (just updated via svn)

Thanks!
Kjow

Kjow wrote

ut only if I have gdb.exe as debugger. If I remove it from options, the project

This may be caused by your anti-virus solution, firewall, or certain drivers.

BitDefender is known to cause this.
Comodo firewall is known to cause this.
I suspect there may be printer drivers that cause this too, but I am not sure.

With some anti virus it is possible to switch to game mode, or similar.

This used to be the case for bitdefender until recently. Now it appears, that bit defender forces itself to be load (as dll) with *every* application. But if entered while in gdb crashes.

There is nothing (as far as I know) that can be done in Lazarus or FPC. If those products, (deliberately or not) behave differently, if the host app is being debugged, then this is to me a fault of the manufacturer of these products.
Alternatively, there may be an issue in gdb itself, that causes certain code to rash. I have no idea, but again, it can't be fixed in Lazarus

Best regards
Martin

2011/4/19 Martin :

Thank you for quick reply,

I had no problems until last Friday (15/04/11) and now, also deactivating my Avira Antivir the problem persist. As printer I have an Epson PX720WD, but that never caused errors to gdb until today.

Damn... :(

Thanks!
Kjow

PS I noticed that when my program crashes (without gdb) Windows return this error: StackHash_fdb0
I don't know if it can help to define the situation...

Hello Lazarus-List,

Tuesday, April 19, 2011, 7:51:35 PM, you wrote:

K> I had no problems until last Friday (15/04/11) and now, also K> deactivating my Avira Antivir the problem persist. K> As printer I have an Epson PX720WD, but that never caused errors to K> gdb until today.

Deactivating Avira is not enougth. I had the same problem a few months ago, so uninstalled Avira and reinstalled it a few days later. Now everything is running fine.

2011/4/19 Jos? Mejuto :

Thanks you,

I will try to re-install it.

Best Regards,
Kjow

Open the "Menu / View / Debug Windows / Debug output" window (before running your app), then start it, and copy, zip, and send the content. Sometimes it gives a clue, sometimes not...

2011/4/19 Martin :

Open the "Menu / View / Debug Windows / Debug output" window (before running your app), then start it, and copy, zip, and send the content. Sometimes it gives a clue, sometimes not...

Well, I found the problem:

from the log you suggested me:
"
*stopped,reason="signal-received",signal-name="SIGSEGV",signal-meaning="Segmentation fault",frame={addr="0x1000b481",func="CMGxSrv!?removeCOMHook@@YAHXZ",args=[],from="C:\\Windows\\SysWOW64\\HsSrv.dll"},thread-id="1",stopped-threads="all" "

HsSrv.dll is part of Asus Xonar DX/D2X drivers and looking for it I found a solution:

"- open msconfig.exe
- go to register "system start" (i have german version of windows 7 64 bit)
- disable HsMgr
- restart windows
READY

The Asus Xonar Driver and Tool works great and the Qt Debugger makes his work"

From here: http://www.qtcentre.org/threads/31948-Segfault-when-running-debug-in-Win7-x64-(gdb-MinGW)?s=2fa738a78700d24096036ca9aa9e02e4

Hoping that this can help someone else.

It works, but unfortunately this disables OpenAL surround... needed to me (in my project). :(

Is it possible to avoid pass a specific dll to gdb?

Thank you!
Kjow

Unfortunately not. This kind of software wants to hook into applications for "better" interaction with this software.
As software you register a dll to be hooked. Then windows loads this dll in all applications loaded.

Marc

...

It works, but unfortunately this disables OpenAL surround... needed to me (in my project). :( Is it possible to avoid pass a specific dll to gdb?

I have no idea. I thought about the same, when I encountered the issue with bitdefender....
I also know that it does not happen in every debugger, bitdefender works in the delphi debugger....

Anyway, I couldn't solve it yet, and for now I got rid of bitdefender, so I am not going to do any work on it soon.

Another idea...
GDB is ot very good at signal handling (SigSegV). Well it catches them reliable, but gdb can not continue afterwards. If those DLL intentionally throw a sigsegv, after installing their own handler, then that may throw off gdb, but not other debuggers. This may be a means off those DLL to protect them self against reverse engineering.

http://www.delorie.com/gnu/docs/gdb/gdb_39.html
You could play with the settings, but you would have to modify the IDE, (debugger/gdbmidebugger.pp)
You can insert code before the line 2950 " ExecuteCommand('set width 50000', []);"

Or maybe easier, run the app in gdb, by hand.

I am not going to reinstall bitdefender to test that.... Maybe one day on my laptop, but not to soon.

Martin

2011/4/20 Martin :

I have no idea. I thought about the same, when I encountered the issue with bitdefender....

[cut]

Thank you all,

I'll look for the best way for me.

Best Regards,
Kjow