From 20424d85f8a07090fd32c6fad343f91b63c730b0 Mon Sep 17 00:00:00 2001
From: Andreas Larsson <andreas@gaisler.com>
Date: Tue, 30 Oct 2012 00:09:46 +0000
Subject: sparc32, leon: Check for existent irq_map entry in
 leon_handle_ext_irq

If an irq is being unlinked concurrently with leon_handle_ext_irq,
irq_map[eirq] might be null in leon_handle_ext_irq. Make sure that
this is not dereferenced.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 arch/sparc/kernel/leon_kernel.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'arch/sparc/kernel/leon_kernel.c')

diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
index f8b6eee40bd..87f60ee6543 100644
--- a/arch/sparc/kernel/leon_kernel.c
+++ b/arch/sparc/kernel/leon_kernel.c
@@ -56,11 +56,13 @@ static inline unsigned int leon_eirq_get(int cpu)
 static void leon_handle_ext_irq(unsigned int irq, struct irq_desc *desc)
 {
 	unsigned int eirq;
+	struct irq_bucket *p;
 	int cpu = sparc_leon3_cpuid();
 
 	eirq = leon_eirq_get(cpu);
-	if ((eirq & 0x10) && irq_map[eirq]->irq) /* bit4 tells if IRQ happened */
-		generic_handle_irq(irq_map[eirq]->irq);
+	p = irq_map[eirq];
+	if ((eirq & 0x10) && p && p->irq) /* bit4 tells if IRQ happened */
+		generic_handle_irq(p->irq);
 }
 
 /* The extended IRQ controller has been found, this function registers it */
-- 
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