[commit] LynxOS: Resume the same thread when receiving a thread create/exit event.

[commit] LynxOS: Resume the same thread when receiving a thread create/exit event.

[Joel Brobecker]

Before this patch, the ptid passed to lynx_resume was completely
ignored, and we used the current_inferior. This resulted in trying
to resume the inferior execution using the wrong ptid after having
received a thread create/exit event, because the inferior_ptid
was still set to the ptid prior to receiving the signal.

gdb/gdbserver/ChangeLog:

        * lynx-low.c (lynx_resume): Use the resume_info parameter
        to determine the ptid for the lynx_ptrace call, unless
        it is equal to minus_one_ptid, in which case we use the
        ptid of the current_inferior.
        (lynx_wait_1): After having received a thread create/exit
        event, resume the inferior's execution using the signaling
        thread's ptid, rather than the old ptid.

Tested on ppc-lynx5.

I hesitated a little before self-approving.  But it seemed sufficiently
straightforward and enough of an improvement (in lynx_resume) that
I allowed myself to go ahead. I will handle comments right away,
if any.

Checked in.

Thanks,
-- 
Joel

---
 gdb/gdbserver/ChangeLog  |   10 ++++++++++
 gdb/gdbserver/lynx-low.c |   11 +++++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 8ba20b0..40bcbab 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,15 @@
 2012-12-17  Joel Brobecker  <brobecker@adacore.com>
 
+	* lynx-low.c (lynx_resume): Use the resume_info parameter
+	to determine the ptid for the lynx_ptrace call, unless
+	it is equal to minus_one_ptid, in which case we use the
+	ptid of the current_inferior.
+	(lynx_wait_1): After having received a thread create/exit
+	event, resume the inferior's execution using the signaling
+	thread's ptid, rather than the old ptid.
+
+2012-12-17  Joel Brobecker  <brobecker@adacore.com>
+
 	* lynx-low.c (lynx_wait_1): Add debug trace before adding
 	new thread.
 
diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c
index 644ff35..3173e3a 100644
--- a/gdb/gdbserver/lynx-low.c
+++ b/gdb/gdbserver/lynx-low.c
@@ -349,14 +349,17 @@ lynx_attach (unsigned long pid)
 static void
 lynx_resume (struct thread_resume *resume_info, size_t n)
 {
-  ptid_t inferior_ptid = thread_to_gdb_id (current_inferior);
   /* FIXME: Assume for now that n == 1.  */
+  ptid_t ptid = resume_info[0].thread;
   const int request = (resume_info[0].kind == resume_step
                        ? PTRACE_SINGLESTEP : PTRACE_CONT);
   const int signal = resume_info[0].sig;
 
+  if (ptid_equal (ptid, minus_one_ptid))
+    ptid = thread_to_gdb_id (current_inferior);
+
   regcache_invalidate ();
-  lynx_ptrace (request, inferior_ptid, 1, signal, 0);
+  lynx_ptrace (request, ptid, 1, signal, 0);
 }
 
 /* Resume the execution of the given PTID.  */
@@ -497,12 +500,12 @@ retry:
 	  case SIGNEWTHREAD:
 	    /* We just added the new thread above.  No need to do anything
 	       further.  Just resume the execution again.  */
-	    lynx_continue (ptid);
+	    lynx_continue (new_ptid);
 	    goto retry;
 
 	  case SIGTHREADEXIT:
 	    remove_thread (find_thread_ptid (new_ptid));
-	    lynx_continue (ptid);
+	    lynx_continue (new_ptid);
 	    goto retry;
 	}
     }
-- 
1.7.0.4

Re: [commit] LynxOS: Resume the same thread when receiving a thread create/exit event.

[Joel Brobecker]

> gdb/gdbserver/ChangeLog:
> 
>         * lynx-low.c (lynx_resume): Use the resume_info parameter
>         to determine the ptid for the lynx_ptrace call, unless
>         it is equal to minus_one_ptid, in which case we use the
>         ptid of the current_inferior.
>         (lynx_wait_1): After having received a thread create/exit
>         event, resume the inferior's execution using the signaling
>         thread's ptid, rather than the old ptid.
[...]
> Checked in.

Actually, the checkin failed, because it depends on:
    [RFC/commit 3/3] Delete unused variable in lynx_resume
    http://www.sourceware.org/ml/gdb-patches/2012-12/msg00544.html

Resolving the conflict due to the dependency feels like undoing
the patch. So I will wait before putting this one in.

-- 
Joel

Re: [commit] LynxOS: Resume the same thread when receiving a thread create/exit event.

[Pedro Alves]

On 12/17/2012 11:26 AM, Joel Brobecker wrote:
> Before this patch, the ptid passed to lynx_resume was completely
> ignored, and we used the current_inferior. This resulted in trying
> to resume the inferior execution using the wrong ptid after having
> received a thread create/exit event, because the inferior_ptid
> was still set to the ptid prior to receiving the signal.
> 
> gdb/gdbserver/ChangeLog:
> 
>         * lynx-low.c (lynx_resume): Use the resume_info parameter
>         to determine the ptid for the lynx_ptrace call, unless
>         it is equal to minus_one_ptid, in which case we use the
>         ptid of the current_inferior.
>         (lynx_wait_1): After having received a thread create/exit
>         event, resume the inferior's execution using the signaling
>         thread's ptid, rather than the old ptid.
> 
> Tested on ppc-lynx5.
> 
> I hesitated a little before self-approving.  But it seemed sufficiently
> straightforward and enough of an improvement (in lynx_resume) that
> I allowed myself to go ahead. I will handle comments right away,
> if any.

Looks fine to me.

-- 
Pedro Alves

Re: [commit] LynxOS: Resume the same thread when receiving a thread create/exit event.

[Joel Brobecker]

> > gdb/gdbserver/ChangeLog:
> > 
> >         * lynx-low.c (lynx_resume): Use the resume_info parameter
> >         to determine the ptid for the lynx_ptrace call, unless
> >         it is equal to minus_one_ptid, in which case we use the
> >         ptid of the current_inferior.
> >         (lynx_wait_1): After having received a thread create/exit
> >         event, resume the inferior's execution using the signaling
> >         thread's ptid, rather than the old ptid.
[...]
> Looks fine to me.

Thanks! Checked in.

-- 
Joel