[Gambas-devel] Problem while running gbx2/3 with gdb

[Benoit Minisini]

On samedi 30 août 2008, Laurent Carlier wrote:
> Le Saturday 30 August 2008 07:35:51 Benoit Minisini, vous avez écrit :
> > On samedi 30 août 2008, Laurent Carlier wrote:
> > > I was not able to run gambas 2/3 apps in gdb, as it failed on dlopen()
> > > calls with an error while loading shared library symbols:
> > >
> > > ---8<---
> > > lordh at ...607...:~/gb2projets/TunnelSDL$ gdb gbx3
> > > GNU gdb 6.8-debian
> > > Copyright (C) 2008 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 "x86_64-linux-gnu"...
> > > (gdb) run
> > > Starting program: /usr/local/bin/gbx3
> > > [Thread debugging using libthread_db enabled]
> > > Error while reading shared library symbols:
> > > Cannot find new threads: generic error
> > > Cannot find new threads: generic error
> > > (gdb) bt
> > > #0  0x00007fe7ac19c7b7 in dl_open_worker () from
> > > /lib64/ld-linux-x86-64.so.2 #1  0x00007fe7ac198366 in _dl_catch_error
> > > () from /lib64/ld-linux-x86-64.so.2 #2  0x00007fe7ac19c0eb in _dl_open
> > > () from /lib64/ld-linux-x86-64.so.2 #3  0x00007fe7abd04fbb in
> > > dlopen_doit () from /lib/libdl.so.2
> > > #4  0x00007fe7ac198366 in _dl_catch_error () from
> > > /lib64/ld-linux-x86-64.so.2 #5  0x00007fe7abd0536c in _dlerror_run ()
> > > from /lib/libdl.so.2
> > > #6  0x00007fe7abd04f21 in dlopen@@GLIBC_2.2.5 () from /lib/libdl.so.2
> > > #7  0x0000000000420999 in LIBRARY_load (lib=0x1eb8400) at
> > > gbx_library.c:468 #8  0x0000000000442377 in COMPONENT_load
> > > (comp=0x1eb83a0) at
> > > gbx_component.c:250
> > > #9  0x0000000000441f4e in COMPONENT_load_all () at gbx_component.c:110
> > > #10 0x0000000000420073 in PROJECT_load () at gbx_project.c:456
> > > #11 0x00000000004330aa in init (file=0x4467b8 ".") at gbx.c:85
> > > #12 0x000000000043366b in main (argc=1, argv=0x7fffb43a4808) at
> > > gbx.c:299 (gdb) quit
> > > ---8<---
> > >
> > > So i was not able to run gbx code inside gdb (and it's not really  easy
> > > to do debugging without gdb !).
> > >
> > > Then i've filled a bug report in debian (i'm running debian sid
> > > x86_64): http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=496494
> > >
> > > And ask for some help on the gdb Mailing List.
> > >
> > > Tonight i've succeeded to find a workaround in forcing linking of gbx
> > > with the libpthread library.
> > >
> > > As far as i know, ubuntu hardy got the same problem, i would ike to ask
> > > you if you got the same problem, and so this is a possible workaround
> > > :-)
> > >
> > > Regards,
> >
> > First, you must run gbx3 with the "-p" option to prevent it from forking
> > at startup. then, I don't see that gdb has crashed, but just breaked. So
> > maybe you can continue the program?
>
> This is with and without preloading (linking with pthread)
> --8<--
> lordh at ...607...:~/gb2projets/TunnelSDL$ gdb gbx3
> GNU gdb 6.8-debian
> Copyright (C) 2008 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 "x86_64-linux-gnu"...
> (gdb) run
> Starting program: /usr/local/bin/gbx3
> [Thread debugging using libthread_db enabled]
> [New Thread 0x7f83ea8ee6e0 (LWP 10259)]
> [New Thread 0x421fe950 (LWP 10262)]
> [Thread 0x421fe950 (LWP 10262) exited]
>
> Program exited normally.
> (gdb) run -p
> Starting program: /usr/local/bin/gbx3 -p
> [Thread debugging using libthread_db enabled]
> [New Thread 0x7f2c3161f6e0 (LWP 10263)]
> [New Thread 0x41457950 (LWP 10264)]
> [Thread 0x41457950 (LWP 10264) exited]
>
> Program exited normally.
> (gdb)
> --8<--
>
> I don't see  a lot of differences.
>

I have committed a patch to always link gbx2 with pthread (not yet for gbx3). 
Does always linking with pthread solve the problem?

-- 
Benoit Minisini