Re: [Xenomai-core] [BUG] module usage counter of xenomai native corrupted (version 2.2.0 and 2.2.5)

[Jan Kiszka <jan.kiszka@domain.hid>]

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Philippe Gerum wrote:
> On Fri, 2006-12-08 at 19:02 +0100, Gilles Chanteperdrix wrote:
>> Jan Kiszka wrote:
>>> Gilles Chanteperdrix wrote:
>>>> Index: ksrc/nucleus/shadow.c
>>>> ===================================================================
>>>> --- ksrc/nucleus/shadow.c	(révision 1930)
>>>> +++ ksrc/nucleus/shadow.c	(copie de travail)
>>>> @@ -888,6 +888,9 @@
>>>>
>>>> 	p = xnthread_archtcb(thread)->user_task;	/* May be != current */
>>>>
>>>> +	if (!xnshadow_thrptd(p))
>>>> +		return;
>>>> +
>>>> 	magic = xnthread_get_magic(thread);
>>>>
>>>> 	for (muxid = 0; muxid < XENOMAI_MUX_NR; muxid++) {
>>>> @@ -1639,8 +1642,6 @@
>>>> 		xnshadow_relax(0);
>>>>
>>>> 	xnlock_get_irqsave(&nklock, s);
>>>> -	/* Prevent wakeup call from xnshadow_unmap(). */
>>>> -	xnshadow_thrptd(p) = NULL;
>>>> 	xnthread_archtcb(thread)->user_task = NULL;
>>>> 	/* xnpod_delete_thread() -> hook -> xnshadow_unmap(). */
>>>> 	xnpod_delete_thread(thread);
>>>
>>> Can't comment on the correctness of the second hunk, but it
>>> unfortunately doesn't change the situation that test case does not
>>> longer terminate with the first hunk applied. May look like a trivial
>>> issue - but it isn't. :->
>>>
>> Indeed. And xnshadow_thrptd(current) == NULL is used by xnpod_schedule,
>> so the patch is probably completely incorrect.
>>
> 
> We should rather check the TCB backlink to the Linux task. Could someone
> who can reproduce this issue, test the following patch? TIA,
> 
> --- ksrc/nucleus/shadow.c	(revision 1931)
> +++ ksrc/nucleus/shadow.c	(working copy)
> @@ -888,6 +888,10 @@
>  
>  	p = xnthread_archtcb(thread)->user_task;	/* May be != current */
>  
> +	xnltt_log_event(xeno_ev_shadowunmap, thread->name, p ? p->pid : -1);
> +	if (!p)
> +		goto renice_and_exit;
> +
>  	magic = xnthread_get_magic(thread);
>  
>  	for (muxid = 0; muxid < XENOMAI_MUX_NR; muxid++) {
> @@ -907,10 +911,6 @@
>  		}
>  	}
>  
> -	xnltt_log_event(xeno_ev_shadowunmap, thread->name, p ? p->pid : -1);
> -	if (!p)
> -		goto renice_and_exit;
> -
>  	xnshadow_thrptd(p) = NULL;
>  
>  	if (p->state != TASK_RUNNING) {
> 

Doesn't work, usage counter is now incremented. BTW, this patch slipped
into SVN with the iobitmap fix.


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