* [PATCH] arm64: make secondary_start_kernel() notrace
@ 2018-06-12 9:07 Zhizhou Zhang
2018-06-12 9:14 ` Mark Rutland
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Zhizhou Zhang @ 2018-06-12 9:07 UTC (permalink / raw)
To: catalin.marinas, will.deacon, james.morse, mark.rutland,
julien.thierry, suzuki.poulose, hoeun.ryu, ard.biesheuvel
Cc: linux-kernel, linux-arm-kernel, zhizhouzhang
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;
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] arm64: make secondary_start_kernel() notrace
2018-06-12 9:07 [PATCH] arm64: make secondary_start_kernel() notrace Zhizhou Zhang
@ 2018-06-12 9:14 ` Mark Rutland
2018-06-12 9:27 ` Suzuki K Poulose
2018-06-18 17:12 ` Catalin Marinas
2 siblings, 0 replies; 4+ messages in thread
From: Mark Rutland @ 2018-06-12 9:14 UTC (permalink / raw)
To: Zhizhou Zhang
Cc: catalin.marinas, will.deacon, james.morse, julien.thierry,
suzuki.poulose, hoeun.ryu, ard.biesheuvel, linux-kernel,
linux-arm-kernel
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
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] arm64: make secondary_start_kernel() notrace
2018-06-12 9:07 [PATCH] arm64: make secondary_start_kernel() notrace Zhizhou Zhang
2018-06-12 9:14 ` Mark Rutland
@ 2018-06-12 9:27 ` Suzuki K Poulose
2018-06-18 17:12 ` Catalin Marinas
2 siblings, 0 replies; 4+ messages in thread
From: Suzuki K Poulose @ 2018-06-12 9:27 UTC (permalink / raw)
To: Zhizhou Zhang, catalin.marinas, will.deacon, james.morse,
mark.rutland, julien.thierry, hoeun.ryu, ard.biesheuvel
Cc: linux-kernel, linux-arm-kernel
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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] arm64: make secondary_start_kernel() notrace
2018-06-12 9:07 [PATCH] arm64: make secondary_start_kernel() notrace Zhizhou Zhang
2018-06-12 9:14 ` Mark Rutland
2018-06-12 9:27 ` Suzuki K Poulose
@ 2018-06-18 17:12 ` Catalin Marinas
2 siblings, 0 replies; 4+ messages in thread
From: Catalin Marinas @ 2018-06-18 17:12 UTC (permalink / raw)
To: Zhizhou Zhang
Cc: will.deacon, james.morse, mark.rutland, julien.thierry,
suzuki.poulose, hoeun.ryu, ard.biesheuvel, linux-kernel,
linux-arm-kernel
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.
--
Catalin
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-06-12 9:07 [PATCH] arm64: make secondary_start_kernel() notrace Zhizhou Zhang
2018-06-12 9:14 ` Mark Rutland
2018-06-12 9:27 ` Suzuki K Poulose
2018-06-18 17:12 ` Catalin Marinas
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