omap: Ptr "isr_reg" tracked as NULL was dereferenced

Value of "isr_reg" pointer is depend on configuration and GPIO method.
Potentially it may have NULL value and it is dereferenced later
in code. Warning and exit from function are added in this case.

Signed-off-by: Evgeny Kuznetsov <EXT-Eugeny.Kuznetsov@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/arm/plat-omap/gpio.c b/arch/arm/plat-omap/gpio.c
index c05c653d167..e0e2fa72526 100644
--- a/arch/arm/plat-omap/gpio.c
+++ b/arch/arm/plat-omap/gpio.c
@@ -1318,6 +1318,10 @@ static void gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
         if (bank->method == METHOD_GPIO_44XX)
                 isr_reg = bank->base + OMAP4_GPIO_IRQSTATUS0;
 #endif
+
+        if (WARN_ON(!isr_reg))
+                goto exit;
+
         while(1) {
                 u32 isr_saved, level_mask = 0;
                 u32 enabled;
@@ -1377,6 +1381,7 @@ static void gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
         configured, we must unmask the bank interrupt only after
         handler(s) are executed in order to avoid spurious bank
         interrupt */
+exit:
         if (!unmasked)
                 desc->chip->unmask(irq);