arm64: make secondary_start_kernel() notrace
authorZhizhou Zhang <zhizhouzhang@asrmicro.com>
Tue, 12 Jun 2018 09:07:37 +0000 (17:07 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 24 Aug 2018 11:09:01 +0000 (13:09 +0200)
commitd22240dd6ab34a69d8e6f07fd74bd53270b554fa
tree6beda83af485b01cc15c6e777a08686e56344a06
parenta929f067a88f0f9a2b02e328f746007f645fa920
arm64: make secondary_start_kernel() notrace

[ 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@arm.com>
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Zhizhou Zhang <zhizhouzhang@asrmicro.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/arm64/kernel/smp.c