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Re: gdb and linuxthreads (A deadlock in linuxthreads.)
- To: Xavier.Leroy@inria.fr (Xavier Leroy)
- Subject: Re: gdb and linuxthreads (A deadlock in linuxthreads.)
- From: hjl@lucon.org (H.J. Lu)
- Date: Mon, 21 Dec 1998 09:15:30 -0800 (PST)
- Cc: libc-hacker@cygnus.com
>
> > Can we use another signal for gdb to indicate a new thread is created?
> > We have RT signal in linux 2.1. It should work. We can fall back to
> > __pthread_sig_cancel if RT signal is not available.
>
> Of course, it would be best to have a third signal. With RT signals,
> that's no problem. But if you're running on a 2.0 kernel, there
> aren't many spare signals to use... Your fallback plan is fine
> provided the two-signal solution still works for those poor 2.0 users.
>
I think it is doable. We have
kernel glibc # of signals gdb
-------------------------------------------------------------
2.0 2.0 2 work
2.0 2.1 2 doesn't work
2.1 2.0 2 work
2.1 2.1 3 work.
The only case gdb doesn't is glibc 2.1 under linux 2.0 due to
__pthread_sig_cancel. I think it is ok. If you can modify
Linuxthreads, I will take care of gdb.
BTW, CLONE_PTRACE breaks gdb.
Thanks.
--
H.J. Lu (hjl@gnu.org)