[PATCH] [ARM] Unconditional call to smp_cross_call on UP crashes

[Pantelis Antoniou]

omap2plus_defconfig builds with SMP & SMP_ON_UP set.
On beagle (which is UP) is_smp() returns false and we don't call
smp_init_cpus which in turn does not initialize smp_cross_call which
remains NULL.

When issuing a reboot we OOPS with a NULL dereference on stop smp_call.

Fixed by checking is_smp in smp_send_stop()
---
 arch/arm/kernel/smp.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 8f46446..2a61335 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -588,6 +588,10 @@ void smp_send_stop(void)
 	unsigned long timeout;
 	struct cpumask mask;
 
+	/* make sure we don't bother if not SMP */
+	if (!is_smp())
+		return;
+
 	cpumask_copy(&mask, cpu_online_mask);
 	cpumask_clear_cpu(smp_processor_id(), &mask);
 	smp_cross_call(&mask, IPI_CPU_STOP);
-- 
1.7.1

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