This is a note to let you know that I've just added the patch titled
cppc_cpufreq: Fix possible null pointer dereference
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cppc_cpufreq-fix-possible-null-pointer-dereference.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f74371f4a004bc5a3e202c790a55920c0fb30424
Author: Aleksandr Mishin <amishin@xxxxxxxxxx>
Date: Mon Apr 8 12:35:36 2024 +0300
cppc_cpufreq: Fix possible null pointer dereference
[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]
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@xxxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 64420d9cfd1ed..15f1d41920a33 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);
