Re: GDB server and threaded application

[Daniel Jacobowitz <drow at mvista dot com>]

No, --attach to a threaded application is _not_ currently supported.

On Wed, Mar 26, 2003 at 04:00:11PM -0800, Kalpesh Jasapara wrote:
> Hello Daniel,
> 
> I believe I have the solib path set correctly and
> all the symbols are being loaded when I connect
> to the remote target.
> 
> BTW I am able to debug core files correctly and the
> core files show all the threads. Its an issue if
> I try to attach to a running multithreaded process.
> 
> gdbserver :12345 --attach <PID>, I just pick up one
> of the PID's of the multithreaded process. I guess 
> this is supported.
> 
> Thanks for all the information. 
> -Kalpesh
> 
> --- Daniel Jacobowitz <drow at mvista dot com> wrote:
> > On Tue, Mar 25, 2003 at 09:39:01PM -0800, Vladimir
> > Gurevich wrote:
> > > Hi Kalpesh!
> > > 
> > > Kalpesh Jasapara wrote:
> > > >I am having a problem with remote gdb debugging
> > > >using gdbserver to work with multi threads.
> > > >The command "info threads" shows only one thread.
> > > 
> > > Here is a relevant excerpt from Wolfgang Denk's
> > > posting from ppc-embedded:
> > 
> > As usual, Wolfgang's answer is somewhat biased.  GDB
> > 5.3's
> > multithreaded debug support is complete, and works
> > very well once you
> > have it set up.  The only thing missing in the FSF
> > tree is the little
> > "[New thread 21211]" messages, which are purely
> > cosmetic; I never came
> > to an agreement about how to implement them in the
> > current protocol.
> > 
> > Neither the version originally in HHL 2.0 nor gdb
> > 5.2.1 supported it
> > however.  Kalpesh said he was trying gdb 5.3, which
> > does.
> > 
> > I would also like to offer Wolfgang a BIG KICK IN
> > THE HEAD.  I have
> > looked at the relevant path on his FTP site that you
> > referenced below;
> > despite his name as the only name on the "ChangeLog
> > entry" in the
> > README and the claim of "we spend some work", it is
> > my work.  I wrote
> > just about every line of that patch.
> > 
> > As usual proper credit would be appreciated.
> > 
> > > 
> > > >Dear Owen,
> > > >
> > > >in message
> > <20020820144703 dot 16442 dot qmail at web20107 dot mail dot yahoo dot com>
> > you wrote:
> > > >
> > > >>
> > > >>I`m trying to debug a multi-threaded application
> > using
> > > >>gdbserver on the remote/target side and I`m
> > having
> > > >>some problems, the output I got is depicted
> > below:
> > > >
> > > >
> > > >I'm not surprised. This is broken in most
> > versions of GDB / gdbserver
> > > >floating around.
> > > >
> > > >
> > > >>I`m using gdbserver5.2.1 (I tried the one from
> > HHL-2.0
> > > >>Journeyman and didn`t worked too) compiled by
> > myself
> > > >>using Mvista HHL 2.0 tools and gdb 5.2.1 on my
> > i386.
> > > >>Am I doing something wrong or remote thread
> > debugging
> > > >>is not supported by gdb? I have read something
> > about
> > > >
> > > >
> > > >Let's say the support is incomplete :-)
> > > >
> > > >>problems with multi-thread application debugging
> > but I
> > > >>thought that it may be OK at this time...
> > > >>Could someone explain to me what`s happening?
> > > >
> > > >
> > > >Check out our ELDK  (see 
> > http://www.denx.de/ELDK);  it  contains  an
> > > >extended  /  bug  fixed  version  of  GDB  /
> > gdbserver; remote target
> > > >debugging of MT applications was one of the areas
> > where we spend some
> > > >work.
> > > >
> > > >If you're just looking for the patches: these can
> > be found on our FTP
> > > >server; the README including description of the
> > test procedure is at
> > >
> >
> >ftp://ftp.denx.de/pub/ppc/patches/README-GDB-MT-Support
> > > >
> > > 
> > > I hope this helps.
> > > 
> > > Cheers,
> > > Vladimir
> > > 
> > > 
> > 
> > -- 
> > Daniel Jacobowitz
> > MontaVista Software                         Debian
> > GNU/Linux Developer
> 
> 
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-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer