2024-04-05 09:42:09

by Aleksandr Mishin

Subject: [PATCH] cppc_cpufreq: Fix possible null pointer dereference

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 <[email protected]>
---
drivers/cpufreq/cppc_cpufreq.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 64420d9cfd1e..5f7e04e8497b 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -741,6 +741,9 @@ 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);
+ if (!policy)
+ return -ENODEV;
+
struct cppc_cpudata *cpu_data = policy->driver_data;
u64 delivered_perf;
int ret;
@@ -822,6 +825,9 @@ 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);
+ if (!policy)
+ return -ENODEV;
+
struct cppc_cpudata *cpu_data = policy->driver_data;
u64 desired_perf;
int ret;
--
2.30.2

2024-04-05 10:39:59

by Mukesh Ojha

Subject: Re: [PATCH] cppc_cpufreq: Fix possible null pointer dereference

On 4/5/2024 3:10 PM, Aleksandr Mishin wrote:
> 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 <[email protected]>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 64420d9cfd1e..5f7e04e8497b 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -741,6 +741,9 @@ 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);
> + if (!policy)
> + return -ENODEV;
> +

You should be doing this after all variable declaration, somewhere

..
..
struct cppc_cpudata *cpu_data;
u64 delivered_perf;
int ret;

if (!policy)
return -ENODEV;

cpu_data = policy->driver_data;
.
.

> struct cppc_cpudata *cpu_data = policy->driver_data;
> u64 delivered_perf;
> int ret;
> @@ -822,6 +825,9 @@ 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);

same here.

> + if (!policy)
> + return -ENODEV;
> +
> struct cppc_cpudata *cpu_data = policy->driver_data;
> u64 desired_perf;
> int ret;

-Mukesh

2024-04-05 10:43:57

by Viresh Kumar

Subject: Re: [PATCH] cppc_cpufreq: Fix possible null pointer dereference

On 05-04-24, 12:40, Aleksandr Mishin wrote:
> 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 <[email protected]>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 64420d9cfd1e..5f7e04e8497b 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -741,6 +741,9 @@ 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);
> + if (!policy)
> + return -ENODEV;
> +
> struct cppc_cpudata *cpu_data = policy->driver_data;
> u64 delivered_perf;
> int ret;
> @@ -822,6 +825,9 @@ 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);
> + if (!policy)
> + return -ENODEV;
> +
> struct cppc_cpudata *cpu_data = policy->driver_data;
> u64 desired_perf;
> int ret;

Does this compile fine ?

--
viresh

2024-04-08 09:39:47

by Aleksandr Mishin

Subject: [PATCH v2] cppc_cpufreq: Fix possible null pointer dereference

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 <[email protected]>
---
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

2024-04-19 06:40:09

by Viresh Kumar

Subject: Re: [PATCH v2] cppc_cpufreq: Fix possible null pointer dereference

On 08-04-24, 12:35, Aleksandr Mishin wrote:
> 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 <[email protected]>
> ---
> v2: Fix mixed declarations
>
> drivers/cpufreq/cppc_cpufreq.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)

Applied. Thanks.

--
viresh