[ARM] Solve buggy smp_processor_id() usage

BUG: using smp_processor_id() in preemptible [00000001] code: opcontrol/427

Resolve this bug by ensuring that we're not using smp_processor_id() in
a preemptable context (by disabling preemption.)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/oprofile/op_model_mpcore.c b/arch/arm/oprofile/op_model_mpcore.c
index 7791da7..75bae06 100644 (file)
--- a/arch/arm/oprofile/op_model_mpcore.c
+++ b/arch/arm/oprofile/op_model_mpcore.c
@@ -200,8 +200,10 @@ static int em_call_function(int (*fn)(void))
        data.fn = fn;
        data.ret = 0;
 
+       preempt_disable();
        smp_call_function(em_func, &data, 1, 1);
        em_func(&data);
+       preempt_enable();
 
        return data.ret;
 }