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Re: Linux ptrace handling of SIGSTOP
- From: Daniel Jacobowitz <drow at false dot org>
- To: Kris Warkentin <kewarken at qnx dot com>
- Cc: GDB <gdb at sources dot redhat dot com>
- Date: Wed, 8 Jun 2005 14:36:36 -0400
- Subject: Re: Linux ptrace handling of SIGSTOP
- References: <42A73A48.1080002@qnx.com>
On Wed, Jun 08, 2005 at 02:34:48PM -0400, Kris Warkentin wrote:
> The Linux documentation for ptrace(PTRACE_CONT, ...., signal) claims
> that signal will be passed unless it is a SIGSTOP. I hit a process that
> I was debugging with a SIGSTOP, gdb of course stops claiming that the
> process got a SIGSTOP. I continue and gdb again says that the process
> was hit with a SIGSTOP. If I continue a second time, the process
> actually continues.
>
> I was debugging child_resume and observed that both times the ptrace was
> being called with SIGSTOP but the second time the process actually
> resumes. This implies to me that the ptrace documentation is not
> completely correct because it seems that the first SIGSTOP is being
> delivered.
>
> Am I missing something? The reason that I ask is that we're not
> currently handling SIGSTOP properly in QNX so I'm trying to find out
> what the expected behaviour should be. Based on the docs, I would have
> thought that the continue would just cause it to resume without further
> interruption.
I don't know - you'd have to ask the kernel developers, i.e. I'm
punting your question to Roland.
--
Daniel Jacobowitz
CodeSourcery, LLC