Re: [PATCH -rt] wrong usage of smp_processor_id()

[Steven Rostedt]

Daniel Walker wrote:

> > > Index: linux-2.6.21/kernel/latency_trace.c
> > > ===================================================================
> > > --- linux-2.6.21.orig/kernel/latency_trace.c
> > > +++ linux-2.6.21/kernel/latency_trace.c
> > > @@ -105,7 +105,7 @@ static inline int DEBUG_WARN_ON(int cond
> > >  #ifdef CONFIG_CRITICAL_IRQSOFF_TIMING
> > >  # ifdef CONFIG_CRITICAL_PREEMPT_TIMING
> > >     static DEFINE_PER_CPU(int, trace_cpu_idle);
> > > -#  define irqs_off_preempt_count() (!__get_cpu_var(trace_cpu_idle) && preempt_count())
> > > +#  define irqs_off_preempt_count() (preempt_count() && !__get_cpu_var(trace_cpu_idle))
> > >  # else
> > >  #  define irqs_off_preempt_count() 0
> > >  # endif


> Isn't it a generic problem? It doesn't look specific to your change
> unless you made some changes to entry.S .

See: http://lkml.org/lkml/2007/4/23/183

Specifically:


 #ifdef CONFIG_CRITICAL_IRQSOFF_TIMING
 # ifdef CONFIG_CRITICAL_PREEMPT_TIMING
-#  define irqs_off_preempt_count() preempt_count()
+   static DEFINE_PER_CPU(int, trace_cpu_idle);
+#  define irqs_off_preempt_count() (!__get_cpu_var(trace_cpu_idle) && 
preempt_count())
 # else
 #  define irqs_off_preempt_count() 0
 # endif
@@ -2153,6 +2154,20 @@ void notrace unmask_preempt_count(unsign
 }
 EXPORT_SYMBOL(unmask_preempt_count);


-- Steve
-
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