Re: GDB problem on RH AS/Clone(). Plz help.

[Jeff Johnston <jjohnstn at redhat dot com>]

Prasanna,

  You should submit a Bugzilla bug to Red Hat.  Red Hat's gdb is a modified 
version of the sources here so you are asking too much of the FSF gdb 
maintainers.  You should start by trying a later version of Red Hat gdb which 
has many more fixes.  Currently, there is a gdb 6.3-based version out there 
which you can download via RHN.

  You also have not provided enough information for anyone to be helpful.  For 
example, what have you done to prove that your program is not actually running 
to completion for a valid reason (e.g. an exit condition is being met with your 
server)?  Breaking on clone() isn't very helpful.  Without knowing much about 
your application, I suggest breaking inside your thread, outside any server 
loop, and at exit points to try and see why the program is running to completion 
(for example, breaking on exit, _exit, pthread_exit, after a join operation, has 
some form of error occurred..).

-- Jeff J.

pras@cycloeastern.com wrote:
> Bump ...
>
> Can somebody please guide me with this clone() issue in gdb or am I on the wrong mailing list?
>
>
> On Wed, Apr 13, 2005 at 11:18:16AM -0400, pras@cycloeastern.com wrote:
>
> > All,
> >
> > This is my first email to this list.
> >
> > I work for a company in that has started using Linux for one of its projects
> > that has traditionally in the past been running on all other big iron *nixes.
> >
> > We just got our first build on RH Enterprise Linux AS release 3 (Taroon Update 4),
> > and gdb attempts fail miserably.
> >
> > Background info:
> >
> > The product is written in C/C++ and is compiled with gcc 3.2.3
> > The gdb version is as follows:
> > GNU gdb Red Hat Linux (6.1post-1.20040607.52rh)
> >
> > I am able to attach to a process and see the stack using backtrace or bt. frame command
> > works and even break command works.
> >
> >
> > When I try to do a 'cont', the server process which is supposed to execute continuously exists normally.
> >
> > This is what I see
> >
> > (gdb) cont
> > Continuing.
> > [New Thread -1245635664 (LWP 8226)]
> > [Thread -1220756560 (LWP 7953) exited]
> >
> > Program exited normally.
> > (gdb)
> >
> > The program is multithreaded and it fails. People at my local LUG suggested that I try to look up problems with
> > clone() system call and GDB. They suggested using PTHREADS could solve the problem. We DO use pthreads and here
> > is the stack(i.e. backtrace). I have set a break point on clone(). Shortly after the program just exits.
> >
> > #0  0x0365e9d0 in clone () from /lib/tls/libc.so.6
> > #1  0x0040a8d7 in do_clone () from /lib/tls/libpthread.so.0
> > #2  0x0040a526 in create_thread () from /lib/tls/libpthread.so.0
> > #3  0x00409f87 in pthread_create@@GLIBC_2.1 () from /lib/tls/libpthread.so.0
> > #4  0x0040a01c in pthread_create@GLIBC_2.0 () from /lib/tls/libpthread.so.0
> > #5  0x004a9f3a in VISThread::_create_thread () from /usr/BDP/lib/libvport_r.so
> > #6  0x004aa0bc in VISThread::run () from /usr/BDP/lib/libvport_r.so
> > #7  0x0142a588 in VISManager::cleanup () from /usr/BDP/lib/liborb_r.so
> > #8  0x0142b063 in VISManager::sig_handler () from /usr/BDP/lib/liborb_r.so
> > #9  0x0142b4a1 in VISThreadSignal::begin () from /usr/BDP/lib/liborb_r.so
> > #10 0x004a8749 in VISThread::_start () from /usr/BDP/lib/libvport_r.so
> > #11 0x00409dec in start_thread () from /lib/tls/libpthread.so.0
> > #12 0x0365ea2a in clone () from /lib/tls/libc.so.6
> >
> >
> > I downloaded 6.3 gdb and compiled it with no options. GDB failed again under that. Please let me know what can be done.
> >
> > Do you guys know what might be going wrong ?
> >
> > --
> > ________________________________________________________________________
> > Prasanna Subash            | WARNING TO ALL PERSONNEL:  Firings will
> > pras@cycloeastern.com      | continue until morale improves. 
> >                           | 
> >                           | 
> > ________________________________________________________________________