[PATCH 4.9 024/130] arm64: make secondary_start_kernel() notrace

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Zhizhou Zhang <zhizhouzhang@xxxxxxxxxxxx>

[ Upstream commit b154886f7892499d0d3054026e19dfb9a731df61 ]

We can't call function trace hook before setup percpu offset.
When entering secondary_start_kernel(), percpu offset has not
been initialized.  So this lead hotplug malfunction.
Here is the flow to reproduce this bug:

echo 0 > /sys/devices/system/cpu/cpu1/online
echo function > /sys/kernel/debug/tracing/current_tracer
echo 1 > /sys/kernel/debug/tracing/tracing_on
echo 1 > /sys/devices/system/cpu/cpu1/online

Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Zhizhou Zhang <zhizhouzhang@xxxxxxxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm64/kernel/smp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -205,7 +205,7 @@ int __cpu_up(unsigned int cpu, struct ta
  * This is the secondary CPU boot entry.  We're using this CPUs
  * idle thread stack, but a set of temporary page tables.
  */
-asmlinkage void secondary_start_kernel(void)
+asmlinkage notrace void secondary_start_kernel(void)
 {
 	struct mm_struct *mm = &init_mm;
 	unsigned int cpu = smp_processor_id();