gpio: mpc8xxx: Prevent NULL pointer deref in demux handler

commit d6de85e85edcc38c9edcde45a0a568818fcddc13 upstream.

commit cfadd838(powerpc/8xxx: Fix interrupt handling in MPC8xxx GPIO
driver) added an unconditional call of chip->irq_eoi() to the demux
handler.

This leads to a NULL pointer derefernce on MPC512x platforms which use
this driver as well.

Make it conditional.

Reported-by: Thomas Wucher <thwucher@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Felix Radensky <felix@embedded-sol.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
index 5cd04b6..edcffd6 100644 (file)
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -163,7 +163,8 @@ static void mpc8xxx_gpio_irq_cascade(unsigned int irq, struct irq_desc *desc)
        if (mask)
                generic_handle_irq(irq_linear_revmap(mpc8xxx_gc->irq,
                                                     32 - ffs(mask)));
-       chip->irq_eoi(&desc->irq_data);
+       if (chip->irq_eoi)
+               chip->irq_eoi(&desc->irq_data);
 }
 
 static void mpc8xxx_irq_unmask(struct irq_data *d)