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Subject[PATCH v2] cpufreq: cppc: Set fie_disabled to FIE_DISABLED if fails to create kworker_fie
Date
The function cppc_freq_invariance_init() may failed to create
kworker_fie, make it more robust by setting fie_disabled to FIE_DISBALED
to prevent an invalid pointer dereference in kthread_destroy_worker(),
which called from cppc_freq_invariance_exit().

Link: https://lore.kernel.org/all/20230816034630.a4hvsj373q6aslk3@vireshk-i7/

Signed-off-by: Liao Chang <liaochang1@huawei.com>
---
drivers/cpufreq/cppc_cpufreq.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 022e3555407c..bff4cde06083 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -220,6 +220,15 @@ static void cppc_cpufreq_cpu_fie_exit(struct cpufreq_policy *policy)
}
}

+static void cppc_freq_invariance_exit(void)
+{
+ if (fie_disabled)
+ return;
+
+ kthread_destroy_worker(kworker_fie);
+ kworker_fie = NULL;
+}
+
static void __init cppc_freq_invariance_init(void)
{
struct sched_attr attr = {
@@ -249,27 +258,22 @@ static void __init cppc_freq_invariance_init(void)
return;

kworker_fie = kthread_create_worker(0, "cppc_fie");
- if (IS_ERR(kworker_fie))
+ if (IS_ERR(kworker_fie)) {
+ pr_warn("%s: failed to create kworker_fie: %ld\n", __func__,
+ PTR_ERR(kworker_fie));
+ fie_disabled = FIE_DISABLED;
return;
+ }

ret = sched_setattr_nocheck(kworker_fie->task, &attr);
if (ret) {
pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__,
ret);
- kthread_destroy_worker(kworker_fie);
- return;
+ cppc_freq_invariance_exit();
+ fie_disabled = FIE_DISABLED;
}
}

-static void cppc_freq_invariance_exit(void)
-{
- if (fie_disabled)
- return;
-
- kthread_destroy_worker(kworker_fie);
- kworker_fie = NULL;
-}
-
#else
static inline void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy)
{
--
2.34.1
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