Here's the patch I used to find out which tasklet was giving me a hard
time with bcm43xx and d80211. I don't really expect this to be applied
anywhere but didn't want to sit on it either.
Signed-off-by: Johannes Berg <[email protected]>
--- wireless-dev.orig/include/linux/interrupt.h 2006-08-13
00:49:46.346865273 +0200
+++ wireless-dev/include/linux/interrupt.h 2006-08-13
16:23:39.449545098 +0200
@@ -14,6 +14,7 @@
#include <asm/atomic.h>
#include <asm/ptrace.h>
#include <asm/system.h>
+#include <linux/stringify.h>
/*
* These correspond to the IORESOURCE_IRQ_* defines in
@@ -267,6 +268,10 @@ struct tasklet_struct
atomic_t count;
void (*func)(unsigned long);
unsigned long data;
+#ifdef CONFIG_DEBUG_TASKLETS
+ char *name;
+ unsigned int reschedule_count;
+#endif
};
#define DECLARE_TASKLET(name, func, data) \
@@ -348,8 +353,25 @@ static inline void tasklet_hi_enable(str
extern void tasklet_kill(struct tasklet_struct *t);
extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned
int cpu);
-extern void tasklet_init(struct tasklet_struct *t,
- void (*func)(unsigned long), unsigned long data);
+extern void _tasklet_init(struct tasklet_struct *t,
+ void (*func)(unsigned long), unsigned long data);
+#ifndef CONFIG_DEBUG_TASKLETS
+#define tasklet_init _tasklet_init
+/* ignore name in the non-debug version, use a macro so the
+ * compiler can discard the string... */
+#define tasklet_init_named(t, func, data, name) \
+ _tasklet_init(t, func, data)
+#else
+#define tasklet_init(t, func, data) do { \
+ _tasklet_init(t, func, data); \
+ (t)->name = __FILE__ ":" __stringify(__LINE__); \
+ } while (0)
+#define tasklet_init_named(t, func, data, name) \
+ do { \
+ _tasklet_init(t, func, data); \
+ (t)->name = (name); \
+ } while (0)
+#endif
/*
* Autoprobing for irqs:
--- wireless-dev.orig/kernel/softirq.c 2006-08-13 00:56:37.206865273
+0200
+++ wireless-dev/kernel/softirq.c 2006-08-13 16:34:31.079545098 +0200
@@ -385,9 +385,22 @@ static void tasklet_action(struct softir
if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
BUG();
t->func(t->data);
+#ifdef CONFIG_DEBUG_TASKLETS
+ t->reschedule_count = 0;
+#endif
tasklet_unlock(t);
continue;
}
+#ifdef CONFIG_DEBUG_TASKLETS
+ /* 10000 is arbitrary... how much should it be?
+ * on my system, 10000 is quite a long time... */
+ if (t->reschedule_count++ > 10000) {
+ printk(KERN_ERR "tasklet %s is scheduled but hasn't been"
+ " enabled for too long!\n", t->name);
+ tasklet_unlock(t);
+ continue;
+ }
+#endif
tasklet_unlock(t);
}
@@ -433,7 +446,7 @@ static void tasklet_hi_action(struct sof
}
-void tasklet_init(struct tasklet_struct *t,
+void _tasklet_init(struct tasklet_struct *t,
void (*func)(unsigned long), unsigned long data)
{
t->next = NULL;
@@ -443,7 +456,7 @@ void tasklet_init(struct tasklet_struct
t->data = data;
}
-EXPORT_SYMBOL(tasklet_init);
+EXPORT_SYMBOL(_tasklet_init);
void tasklet_kill(struct tasklet_struct *t)
{
--- wireless-dev.orig/lib/Kconfig.debug 2006-08-13 01:00:56.016865273
+0200
+++ wireless-dev/lib/Kconfig.debug 2006-08-13 16:00:15.419545098 +0200
@@ -93,6 +93,16 @@ config SCHEDSTATS
application, you can say N to avoid the very slight overhead
this adds.
+config DEBUG_TASKLETS
+ bool "Debug runaway tasklets"
+ depends on DEBUG_KERNEL
+ help
+ If you say Y here, additional code will be inserted into the
+ lowlevel tasklet code in order to debug tasklets that are
+ scheduled but not enabled. If such a tasklet is found and
+ not enabled within a number of iterations, it is un-scheduled
+ and the kernel reports it.
+
config DEBUG_SLAB
bool "Debug slab memory allocations"
depends on DEBUG_KERNEL && SLAB
-
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