[PATCH] cpufreq: qcom-cpufreq-hw: Fix possible double free

[Guangshuo Li]

qcom_cpufreq.data is allocated with devm_kzalloc() in probe() as an
array of per-domain data. qcom_cpufreq_hw_cpu_init() stores a pointer to
one element of this array in policy->driver_data.

qcom_cpufreq_hw_cpu_exit() currently calls kfree() on policy->driver_data.
This is not valid because the memory is devm-managed. For the first
domain, this can free the devm-managed allocation while the devres entry
is still active, leading to a possible double free when the platform
device is later detached. For other domains, the pointer may refer to an
element inside the array rather than the allocation base.

Remove the kfree(data) call and let devres release qcom_cpufreq.data.

This issue was found by a static analysis tool I am developing.

Fixes: 054a3ef683a1 ("cpufreq: qcom-hw: Allocate qcom_cpufreq_data during probe")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
---
 drivers/cpufreq/qcom-cpufreq-hw.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index ea9a20d27b8f..ef19faedbfec 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -578,7 +578,6 @@ static void qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
 	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 	qcom_cpufreq_hw_lmh_exit(data);
 	kfree(policy->freq_table);
-	kfree(data);
 }
 
 static void qcom_cpufreq_ready(struct cpufreq_policy *policy)
-- 
2.43.0