[PATCH] cpufreq: amd-pstate: fix kernel hang issue while amd-pstate unregistering

Perry Yuan
2023-01-06T05:51:12Z

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