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Message-ID: <20230110151029.1945544-1-perry.yuan@amd.com>
Date: Tue, 10 Jan 2023 23:10:29 +0800
From: Perry Yuan <perry.yuan@....com>
To: <rafael.j.wysocki@...el.com>, <Mario.Limonciello@....com>,
<ray.huang@....com>, <viresh.kumar@...aro.org>
CC: <Deepak.Sharma@....com>, <Nathan.Fontenot@....com>,
<Alexander.Deucher@....com>, <Shimmer.Huang@....com>,
<Xiaojian.Du@....com>, <Li.Meng@....com>, <wyes.karny@....com>,
<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v3] cpufreq: amd-pstate: fix kernel hang issue while amd-pstate unregistering
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.
Fixes: 1d215f0319 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State")
Acked-by: Huang Rui <ray.huang@....com>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>
Tested-by: Wyes Karny <wyes.karny@....com>
Signed-off-by: Perry Yuan <perry.yuan@....com>
Cc: stable@...r.kernel.org
v3: add Fixes tag
v2: add test-by flag from Wyes.
---
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
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