genirq: stackdump after the "Trying to free already-free IRQ" message

these bugs are harder to find than they seem, a stackdump helps.

make it dependent on CONFIG_DEBUG_SHIRQ so that people can turn it off
if it annoys them.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 1f314221d534..438a01464287 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -479,6 +479,9 @@ void free_irq(unsigned int irq, void *dev_id)
                         return;
                 }
                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
+#ifdef CONFIG_DEBUG_SHIRQ
+                dump_stack();
+#endif
                 spin_unlock_irqrestore(&desc->lock, flags);
                 return;
         }