| Message ID | 1528794457-14129-1-git-send-email-zhizhouzhang@asrmicro.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 12/06/18 10:07, 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) > { > u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; > struct mm_struct *mm = &init_mm; > Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> I think this should go to stable releases as well. Suzuki
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> Queued for 4.18. Thanks.
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) { u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; struct mm_struct *mm = &init_mm;
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(-)