Re: Problem with hwlat detector in smp_processor_id()

[Carsten Emde <Carsten.Emde@osadl.org>]

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On 07/09/2009 01:32 PM, Wolfgang Steinwender wrote:

> [..] When I'm trying the hardware latency test (hwlatdetect.py) I'm
> getting the following messages:
> hwlat_detector: version 1.0.0
> BUG: using smp_processor_id() in preemptible [00000000] code:
> hwlatdetect/3755
> caller is debug_sample_fread+0x138/0x1ea [hwlat_detector] [..]
Does the attached patch help?

	Carsten.

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Index: linux-2.6.29.5-rt22/drivers/misc/hwlat_detector.c
===================================================================
--- linux-2.6.29.5-rt22.orig/drivers/misc/hwlat_detector.c
+++ linux-2.6.29.5-rt22/drivers/misc/hwlat_detector.c
@@ -191,17 +191,11 @@ static struct sample *buffer_get_sample(
 	if (!sample)
 		return NULL;
 
-	/* ring_buffers are per-cpu but we just want any value */
-	/* so we'll start with this cpu and try others if not */
-	/* Steven is planning to add a generic mechanism */
 	mutex_lock(&ring_buffer_mutex);
-	e = ring_buffer_consume(ring_buffer, smp_processor_id(), NULL);
-	if (!e) {
-		for_each_online_cpu(cpu) {
-			e = ring_buffer_consume(ring_buffer, cpu, NULL);
-			if (e)
-				break;
-		}
+	for_each_online_cpu(cpu) {
+		e = ring_buffer_consume(ring_buffer, cpu, NULL);
+		if (e)
+			break;
 	}
 
 	if (e) {