From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 11 Apr 2006 16:01:23 +0200
From: Jan Kiszka <jan.kiszka@domain.hid>
MIME-Version: 1.0
Subject: Re: [Xenomai-core] [PATCH] Fixs doxygen doc on
	rt_queue_read	in	ksrc/native/queue.c (for SVN version)
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To: Rodrigo Rosenfeld Rosas <lbocseg@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

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[a few interruptions later]

Jan Kiszka wrote:
> Rodrigo Rosenfeld Rosas wrote:
>> BTW, please, could someone confirm the rt_task_delete(NULL) bug in SVN=
?
>=20
> Half-confirmed, there is something fishy. I'm struggling with the
> debugger ATM, not sure yet who's wrong ;). It tells me rt_task_delete o=
f
> the skin module is entered with task !=3D NULL...

=2E..which turns out to be fine, just appears redundant to me when
comparing __rt_task_delete and rt_task_delete for the task=3DNULL case.

Anyway, leaving a native task with rt_task_delete(NULL) raises SIGKILL
to the whole process instead of just the task (pthread). This lets your
program terminate unexpectedly - I would say: a bug. And this doesn't
happen with 2.1?

I guess the easiest way to solve this is to catch NULL in userspace and
call pthread_exit() in favour of the skin service (the POSIX skin uses
pthread_exit anyway), see attached patch. Someone just has to confirm
that there will be no problem hidden by this approach.

Jan


PS: What's the reason for "if (err =3D=3D -ESRCH) return 0" in
src/skins/native/task.c, rt_task_delete? Why is that error generate in
the first place if it is zeroed out here?

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Index: src/skins/native/task.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- src/skins/native/task.c	(revision 923)
+++ src/skins/native/task.c	(working copy)
@@ -212,7 +212,10 @@ int rt_task_delete (RT_TASK *task)
 {
     int err;
=20
-    if (task && task->opaque2) {
+    if (!task)
+	pthread_exit(NULL);
+
+    if (task->opaque2) {
 	err =3D pthread_cancel((pthread_t)task->opaque2);
 	if (err)
 	    return -err;

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