[PATCH] IRQ: Add a check for uninitialized irqs.

From: raghu . prabhu13
Date: Sun Sep 09 2012 - 15:26:11 EST

From: Raghavendra D Prabhu <rprabhu@xxxxxxxxxxx>

Errors like "do_IRQ: 0.84 No Irq handler for vector (irq -1)" have been reported
earlier filling up the console/logs. So this adds a condition to check for
uninitialized irqs so that it exits early and doesn't proceed further. Also, irq
is made a signed integer, since if it is not mapped to a vector, it will be
assigned -1 which will be UINT_MAX otherwise.

Signed-off-by: Raghavendra D Prabhu <rprabhu@xxxxxxxxxxx>
arch/x86/kernel/irq.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index d44f782..ddba63a 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -184,21 +184,24 @@ unsigned int __irq_entry do_IRQ(struct pt_regs *regs)

/* high bit used in ret_from_ code */
unsigned vector = ~regs->orig_ax;
- unsigned irq;
+ int irq;


- irq = __this_cpu_read(vector_irq[vector]);
+ if (unlikely((irq = __this_cpu_read(vector_irq[vector])) == -1)) {
+ pr_emerg_ratelimited("IRQ handler not setup for vector %u", vector);
+ goto err_exit;
+ }

if (!handle_irq(irq, regs)) {

- if (printk_ratelimit())
- pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",
- __func__, smp_processor_id(), vector, irq);
+ pr_emerg_ratelimited("%s: %d.%d No irq handler for vector (irq %u)\n",
+ __func__, smp_processor_id(), vector, irq);



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