From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Fri, 21 Nov 2008 15:59:59 +0100
From: Philippe Gerum <rpm@xenomai.org>
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Subject: Re: [Xenomai-core] [PATCH] Catch multiple xnshadow_map attempts
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To: Jan Kiszka <jan.kiszka@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

Jan Kiszka wrote:
> Philippe Gerum wrote:
>> Jan Kiszka wrote:
>>> My customer managed to find another hidden door to Xenomai's hell:
>>> Trying to create a Xenomai POSIX thread from within a native thread. A
>>> think the other way around would "work" as well. The precise scenario
>>> was native thread -> dlopen(libs that's linked against libpthread_rt) ->
>>> __init_posix_interface -> __wrap_pthread_setschedparam -> oops. That
>>> scenario revealed two more issues in fact.
>>>
>>> Here is a patch to remove this hell gate by catching xnshadow_map
>>> invocations from withing already mapped shadow thread.
>>>
>> Any reason why the XNMAPPED predicate did not work in your case?
> 
> Sorry, which one? Keep in mind that the thread thrown at the second
> xnshadow_map is a virgin one, just allocated from scratch.
>

Ok, got it, it's the converse case, so let's deal for that:

--- ksrc/nucleus/shadow.c	(revision 4411)
+++ ksrc/nucleus/shadow.c	(working copy)
@@ -1331,7 +1331,7 @@
  * case, the real-time mapping operation has failed globally, and no
  * Xenomai resource remains attached to it.
  *
- * - -EINVAL is returned if the thread control block does not bear the
+ * - -EBUSY is returned if the thread control block does not bear the
  * XNSHADOW bit, or if the thread has already been mapped.
  *
  * Environments:
@@ -1354,8 +1354,8 @@
 	if (!xnthread_test_state(thread, XNSHADOW))
 		return -EINVAL;

-	if (xnthread_test_state(thread, XNMAPPED))
-		return -EINVAL;
+	if (xnshadow_thread(current) || xnthread_test_state(thread, XNMAPPED))
+		return -EBUSY;

 	if (!access_wok(u_mode, sizeof(*u_mode)))
 		return -EFAULT;

> Jan
> 
>>> Jan
>>>
>>> ---
>>>  ChangeLog             |    5 +++++
>>>  ksrc/nucleus/shadow.c |    5 +++++
>>>  2 files changed, 10 insertions(+)
>>>
>>> Index: xenomai/ksrc/nucleus/shadow.c
>>> ===================================================================
>>> --- xenomai.orig/ksrc/nucleus/shadow.c
>>> +++ xenomai/ksrc/nucleus/shadow.c
>>> @@ -1334,6 +1334,8 @@ void xnshadow_exit(void)
>>>   * - -EINVAL is returned if the thread control block does not bear the
>>>   * XNSHADOW bit, or if the thread has already been mapped.
>>>   *
>>> + * - -EBUSY is returned if the current Linux task is already mapped.
>>> + *
>>>   * Environments:
>>>   *
>>>   * This service can be called from:
>>> @@ -1351,6 +1353,9 @@ int xnshadow_map(xnthread_t *thread, xnc
>>>  	unsigned muxid, magic;
>>>  	int err;
>>>
>>> +	if (xnshadow_thread(current))
>>> +		return -EBUSY;
>>> +
>>>  	if (!xnthread_test_state(thread, XNSHADOW))
>>>  		return -EINVAL;
>>>
>>> Index: xenomai/ChangeLog
>>> ===================================================================
>>> --- xenomai.orig/ChangeLog
>>> +++ xenomai/ChangeLog
>>> @@ -1,3 +1,8 @@
>>> +2008-11-21  Jan Kiszka  <jan.kiszka@domain.hid>
>>> +
>>> +	* ksrc/nucleus/shadow.c (xnshadow_map): Reject already mapped
>>> +	tasks with -EBUSY.
>>> +
>>>  2008-11-16  Philippe Gerum  <rpm@xenomai.org>
>>>
>>>  	* ksrc/arch/blackfin/patches: Upgrade to to
>>
> 
> 


-- 
Philippe.