[lvc-project] [PATCH v2] cppc_cpufreq: Fix possible null pointer dereference
Aleksandr Mishin
amishin at t-argos.ru
Mon Apr 8 12:35:36 MSK 2024
cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin at t-argos.ru>
---
v2: Fix mixed declarations
drivers/cpufreq/cppc_cpufreq.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 64420d9cfd1e..15f1d41920a3 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -741,10 +741,15 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
{
struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
- struct cppc_cpudata *cpu_data = policy->driver_data;
+ struct cppc_cpudata *cpu_data;
u64 delivered_perf;
int ret;
+ if (!policy)
+ return -ENODEV;
+
+ cpu_data = policy->driver_data;
+
cpufreq_cpu_put(policy);
ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t0);
@@ -822,10 +827,15 @@ static struct cpufreq_driver cppc_cpufreq_driver = {
static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
- struct cppc_cpudata *cpu_data = policy->driver_data;
+ struct cppc_cpudata *cpu_data;
u64 desired_perf;
int ret;
+ if (!policy)
+ return -ENODEV;
+
+ cpu_data = policy->driver_data;
+
cpufreq_cpu_put(policy);
ret = cppc_get_desired_perf(cpu, &desired_perf);
--
2.30.2
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