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Re: RFA[threads]: Fork event updates, part the thirteenth
- From: Michael Snyder <msnyder at redhat dot com>
- To: Daniel Jacobowitz <drow at mvista dot com>
- Cc: gdb-patches at sources dot redhat dot com, kettenis at gnu dot org
- Date: Mon, 06 Jan 2003 15:53:52 -0800
- Subject: Re: RFA[threads]: Fork event updates, part the thirteenth
- Organization: Red Hat, Inc.
- References: <20021215213952.GA3923@nevyn.them.org>
Daniel Jacobowitz wrote:
>
> Now is where it starts to get interesting. Michael, I mentioned this patch
> to you at lunch last week. If you take a short-lived program, run it, and
> detach it, and run it again, you'll see the exit of the _previous_ copy.
> Then GDB gets hopelessly confused. I have a testcase for this which I'll
> post in a moment.
>
> The reason it's included here is that that's essentially what happens if you
> are using "set follow-fork-mode child". We detach from the parent, which
> exits, confusing GDB.
>
> Is this OK?
Hi Dan,
Please excuse the delay. This seems OK. In child_wait,
would it be possible to add a check to see if the exiting
process is in our lwp list?
Michael
>
> --
> Daniel Jacobowitz
> MontaVista Software Debian GNU/Linux Developer
>
> 2002-12-15 Daniel Jacobowitz <drow@mvista.com>
>
> * lin-lwp.c (child_wait): Ignore exit statuses for processes other
> than inferior_ptid.
> (lin_lwp_wait): Ignore exit statuses for unknown LWPs.
>
> Index: lin-lwp.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/lin-lwp.c,v
> retrieving revision 1.39
> diff -u -p -r1.39 lin-lwp.c
> --- lin-lwp.c 9 Dec 2002 18:41:42 -0000 1.39
> +++ lin-lwp.c 15 Dec 2002 21:16:34 -0000
> @@ -964,6 +964,14 @@ child_wait (ptid_t ptid, struct target_w
> pid = waitpid (GET_PID (ptid), &status, __WCLONE);
> save_errno = errno;
>
> + /* Make sure we don't report an event for the exit of the
> + original program, if we've detached from it. */
> + if (pid != -1 && ! WIFSTOPPED (status) && pid != GET_PID (inferior_ptid))
> + {
> + pid = -1;
> + save_errno = EINTR;
> + }
> +
> clear_sigio_trap ();
> clear_sigint_trap ();
> }
> @@ -1091,6 +1099,17 @@ lin_lwp_wait (ptid_t ptid, struct target
> gdb_assert (pid == -1 || lwpid == pid);
>
> lp = find_lwp_pid (pid_to_ptid (lwpid));
> +
> + /* Make sure we don't report an event for the exit of an LWP not in
> + our list, i.e. not part of the current process. This can happen
> + if we detach from a program we original forked and then it
> + exits. */
> + if (! WIFSTOPPED (status) && ! lp)
> + {
> + status = 0;
> + continue;
> + }
> +
> if (! lp)
> {
> lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid)));