Re: Debugging and NPTL

Ali Ijaz Sheikh <[email protected]> Mon, 17 May 2004 16:59:30 -0400
Newsgroups gmane.comp.lib.phil
Message-ID <[email protected]>
Quoting Daniel Jacobowitz <[email protected]>:

> On Mon, May 17, 2004 at 03:11:45PM -0400, Ali Ijaz Sheikh wrote:
> >
> > Hi,
> >
> > I have recently started seeing some problems with debugging of
> multithreaded
> > applications with NPTL on 2.6 series kernels.  It seems that GDB is n=
o
> longer
> > being informed of the events occurring in the child threads because
> > create_thread (nptl/sysdeps/pthread/create_thread.c) routine does not=
 pass
> the
> > CLONE_PTRACE flag to the clone system call.  For example, if the chil=
d
> thread
> > gets a SEGV, the whole thread group is terminated without GDB ever be=
ing
> told.
> >
> > When creating a thread in a thread group that is being ptraced, shoul=
dn't
> the
> > child thread be created with a CLONE_PTRACE?  It this a nptl bug?  Or=
 is
> this
> > GDB's fault?
> >
> > A simple program that creates a thread and does raise(SIGSEGV) in the=
 child
> > thread can be used to reproduce this problem.  Try running that in gd=
b.
>
> No, it should not be using CLONE_PTRACE.  You didn't say what version
> of GDB you were using; you may want to try a newer one.
>
> --
> Daniel Jacobowitz
>

I have tried this with GDB 6.0 and 6.1.

-Ali


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