* [PATCH] cpufreq: amd-pstate: fix kernel hang issue while amd-pstate unregistering
@ 2023-01-06 5:48 Perry Yuan
2023-01-09 15:38 ` Wyes Karny
0 siblings, 1 reply; 2+ messages in thread
From: Perry Yuan @ 2023-01-06 5:48 UTC (permalink / raw)
To: rafael.j.wysocki, Mario.Limonciello, ray.huang, viresh.kumar
Cc: Deepak.Sharma, Nathan.Fontenot, Alexander.Deucher, Shimmer.Huang,
Xiaojian.Du, Li.Meng, wyes.karny, linux-pm, linux-kernel
In the amd_pstate_adjust_perf(), there is one cpufreq_cpu_get() call to
increase increments the kobject reference count of policy and make it as
busy. Therefore, a corresponding call to cpufreq_cpu_put() is needed to
decrement the kobject reference count back, it will resolve the kernel
hang issue when unregistering the amd-pstate driver and register the
`amd_pstate_epp` driver instance.
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Cc: stable@vger.kernel.org
---
drivers/cpufreq/amd-pstate.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 204e39006dda..c17bd845f5fc 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -307,6 +307,7 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
max_perf = min_perf;
amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true);
+ cpufreq_cpu_put(policy);
}
static int amd_get_min_freq(struct amd_cpudata *cpudata)
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] cpufreq: amd-pstate: fix kernel hang issue while amd-pstate unregistering
2023-01-06 5:48 [PATCH] cpufreq: amd-pstate: fix kernel hang issue while amd-pstate unregistering Perry Yuan
@ 2023-01-09 15:38 ` Wyes Karny
0 siblings, 0 replies; 2+ messages in thread
From: Wyes Karny @ 2023-01-09 15:38 UTC (permalink / raw)
To: Perry Yuan, rafael.j.wysocki, Mario.Limonciello, ray.huang,
viresh.kumar
Cc: Deepak.Sharma, Nathan.Fontenot, Alexander.Deucher, Shimmer.Huang,
Xiaojian.Du, Li.Meng, linux-pm, linux-kernel
On 1/6/2023 11:18 AM, Perry Yuan wrote:
> In the amd_pstate_adjust_perf(), there is one cpufreq_cpu_get() call to
> increase increments the kobject reference count of policy and make it as
> busy. Therefore, a corresponding call to cpufreq_cpu_put() is needed to
> decrement the kobject reference count back, it will resolve the kernel
> hang issue when unregistering the amd-pstate driver and register the
> `amd_pstate_epp` driver instance.
>
> Acked-by: Huang Rui <ray.huang@amd.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
> Cc: stable@vger.kernel.org
> ---
> drivers/cpufreq/amd-pstate.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 204e39006dda..c17bd845f5fc 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -307,6 +307,7 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
> max_perf = min_perf;
>
> amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true);
> + cpufreq_cpu_put(policy);
> }
>
> static int amd_get_min_freq(struct amd_cpudata *cpudata)
--
Thanks & Regards,
Wyes
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