Re: [Xenomai-help] Xenomai Bug: rt_intr_create with NULL-name leads to Kernel oops in /proc/xenomai/irq

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

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M. Koehrer wrote:
> Hi all,
> 
> I am just trying out the interrupt mechanism of Xenomai.
> For that, I have create a kernel module that uses rt_intr_create (from the native skin) to
> create an IRQ handler. So far that looks fine.
> However, I noticed, that I have to pass a non-NULL argument  name to rt_intr_create().
> Otherwise, cat /proc/xenomai/irq crashes with a kernel oops.
> I think this is a bug as the API documentation allows the usage of a NULL name in rt_intr_create.
> Probably, the zero pointer will not be checked in the proc reading function.
> I am using 2.6.19.1 on a Pentium 4 (UP) with Xenomai 2.3.
> 
> I have enclosed a minimum kernel module that leads to a kernel oops to see the effect.
> 

Untested, but this patch should fix the issue - also for RTDM drivers
passing a NULL name to rtdm_irq_request (which was not forbidden so far
too). Nevertheless, passing a name is recommended to ease the system
diagnosis. Maybe the native doc should be changed in this regard too (I
already did so for RTDM in 2.3 and trunk).

Jan

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Index: ChangeLog
===================================================================
--- ChangeLog	(revision 2056)
+++ ChangeLog	(working copy)
@@ -1,3 +1,8 @@
+2007-01-10  Jan Kiszka  <jan.kiszka@domain.hid>
+
+	* ksrc/nucleus/intr.c (xnintr_init): Always set xnintr::name to
+	non-NULL content.
+
 2007-01-04  Philippe Gerum  <rpm@xenomai.org>
 
 	* include/nucleus/timebase.h (xntbase_convert): Add time base
Index: ksrc/nucleus/intr.c
===================================================================
--- ksrc/nucleus/intr.c	(revision 2056)
+++ ksrc/nucleus/intr.c	(working copy)
@@ -490,7 +490,7 @@ int xnintr_mount(void) { return 0; }
  * therefore it must be allocated in permanent memory.
  *
  * @param name An ASCII string standing for the symbolic name of the
- * interrupt object.
+ * interrupt object or NULL ("<unknown>" will be applied then).
  *
  * @param irq The hardware interrupt channel associated with the
  * interrupt object. This value is architecture-dependent. An
@@ -541,7 +541,7 @@ int xnintr_init(xnintr_t *intr,
 	intr->isr = isr;
 	intr->iack = iack;
 	intr->cookie = NULL;
-	intr->name = name;
+	intr->name = name ? : "<unknown>";
 	intr->flags = flags;
 	intr->unhandled = 0;
 	memset(&intr->stat, 0, sizeof(intr->stat));

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