From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 11 Apr 2006 22:25:03 +0200
From: Philippe Gerum <rpm@xenomai.org>
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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: Jan Kiszka <jan.kiszka@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

Jan Kiszka wrote:
> [a few interruptions later]
> 
> Jan Kiszka wrote:
> 
>>Rodrigo Rosenfeld Rosas wrote:
>>
>>>BTW, please, could someone confirm the rt_task_delete(NULL) bug in SVN?
>>
>>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 of
>>the skin module is entered with task != NULL...
> 
> 
> ...which turns out to be fine, just appears redundant to me when
> comparing __rt_task_delete and rt_task_delete for the task=NULL 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?
>

It's a side-effect of a recent bug fix in ksrc/nucleus/shadow.c; now 
killing a thread raises a group signal wiping out the entire process. 
Ok, it's a bit drastic, will fix.

> 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.

Passing NULL needs to work including from user-space; the kernel-space 
is ok with this, and the API must behave the same way regardless of the 
execution space. Should fix as needed.

> 
> Jan
> 
> 
> PS: What's the reason for "if (err == -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?
> 
> 
> ------------------------------------------------------------------------
> 
> Index: src/skins/native/task.c
> ===================================================================
> --- 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;
>  
> -    if (task && task->opaque2) {
> +    if (!task)
> +	pthread_exit(NULL);
> +
> +    if (task->opaque2) {
>  	err = pthread_cancel((pthread_t)task->opaque2);
>  	if (err)
>  	    return -err;


-- 

Philippe.