Messages in this thread | | | Date | Tue, 12 Jun 2018 10:14:41 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH] arm64: make secondary_start_kernel() notrace |
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On Tue, Jun 12, 2018 at 05:07:37PM +0800, Zhizhou Zhang wrote: > 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 > > Signed-off-by: Zhizhou Zhang <zhizhouzhang@asrmicro.com> > --- > arch/arm64/kernel/smp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index f3e2e3ae..11b0f30 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -179,7 +179,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) > * 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) > +notrace asmlinkage void secondary_start_kernel(void)
Minor nit: can we please keep asmlinkage first, e.g.
asmlinkage notrace void secondary_start_kernel(void)
Either way:
Acked-by: Mark Rutland <mark.rutland@arm.com>
Thanks, Mark.
> { > u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; > struct mm_struct *mm = &init_mm; > -- > 1.9.1 >
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