[PATCH] genirq: more verbose debugging on unexpected IRQ vectors

One frequent sign of IRQ handling bugs is the appearance of unexpected
vectors.  Print out all the IRQ state in that case.  We dont want this patch
upstream, but it is useful during initial testing.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 42 insertions, 0 deletions

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 01fc7f79d74a..5a360dd4331b 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -24,6 +24,7 @@
 void fastcall
 handle_bad_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 {
+        print_irq_desc(irq, desc);
         kstat_this_cpu.irqs[irq]++;
         ack_bad_irq(irq);
 }
@@ -61,6 +62,7 @@ struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned = {
  */
 static void ack_bad(unsigned int irq)
 {
+        print_irq_desc(irq, irq_desc + irq);
         ack_bad_irq(irq);
 }
 
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 2ba8ae3c8e96..08a849a22447 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -22,3 +22,43 @@ static inline void unregister_handler_proc(unsigned int irq,
                                            struct irqaction *action) { }
 #endif
 
+/*
+ * Debugging printout:
+ */
+
+#include <linux/kallsyms.h>
+
+#define P(f) if (desc->status & f) printk("%14s set\n", #f)
+
+static inline void print_irq_desc(unsigned int irq, struct irq_desc *desc)
+{
+        printk("irq %d, desc: %p, depth: %d, count: %d, unhandled: %d\n",
+                irq, desc, desc->depth, desc->irq_count, desc->irqs_unhandled);
+        printk("->handle_irq():  %p, ", desc->handle_irq);
+        print_symbol("%s\n", (unsigned long)desc->handle_irq);
+        printk("->chip(): %p, ", desc->chip);
+        print_symbol("%s\n", (unsigned long)desc->chip);
+        printk("->action(): %p\n", desc->action);
+        if (desc->action) {
+                printk("->action->handler(): %p, ", desc->action->handler);
+                print_symbol("%s\n", (unsigned long)desc->action->handler);
+        }
+
+        P(IRQ_INPROGRESS);
+        P(IRQ_DISABLED);
+        P(IRQ_PENDING);
+        P(IRQ_REPLAY);
+        P(IRQ_AUTODETECT);
+        P(IRQ_WAITING);
+        P(IRQ_LEVEL);
+        P(IRQ_MASKED);
+#ifdef CONFIG_IRQ_PER_CPU
+        P(IRQ_PER_CPU);
+#endif
+        P(IRQ_NOPROBE);
+        P(IRQ_NOREQUEST);
+        P(IRQ_NOAUTOEN);
+}
+
+#undef P
+