cpufreq: scpi: Prevent null pointer dereference in scpi_cpufreq_get_rate()

[PATCH] cpufreq: scpi: Prevent null pointer dereference in scpi_cpufreq_get_rate()

Posted by Charles Han 1 year, 4 months ago

cpufreq_cpu_get_raw() may return NULL if the cpu is not in
policy->cpus cpu mask and it will cause null pointer dereference.
Prevent null pointer dereference in scpi_cpufreq_get_rate().

Fixes: 343a8d17fa8d ("cpufreq: scpi: remove arm_big_little dependency")
Signed-off-by: Charles Han <hanchunchao@inspur.com>
---
 drivers/cpufreq/scpi-cpufreq.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cpufreq/scpi-cpufreq.c b/drivers/cpufreq/scpi-cpufreq.c
index cd89c1b9832c..c888ed3a0de9 100644
--- a/drivers/cpufreq/scpi-cpufreq.c
+++ b/drivers/cpufreq/scpi-cpufreq.c
@@ -30,6 +30,9 @@ static struct scpi_ops *scpi_ops;
 static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
 {
 	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
+	if (unlikely(!policy))
+		return 0;
+
 	struct scpi_data *priv = policy->driver_data;
 	unsigned long rate = clk_get_rate(priv->clk);
 
-- 
2.31.1

Re: [PATCH] cpufreq: scpi: Prevent null pointer dereference in scpi_cpufreq_get_rate()

Posted by Sudeep Holla 1 year, 4 months ago

On Mon, Dec 30, 2024 at 05:31:59PM +0800, Charles Han wrote:
> cpufreq_cpu_get_raw() may return NULL if the cpu is not in
> policy->cpus cpu mask and it will cause null pointer dereference.
> Prevent null pointer dereference in scpi_cpufreq_get_rate().
>

Can you please fix such occurrences in other places too ?
I see it in apple-soc-cpufreq.c and scmi-cpufreq.c as well.

> Fixes: 343a8d17fa8d ("cpufreq: scpi: remove arm_big_little dependency")
> Signed-off-by: Charles Han <hanchunchao@inspur.com>
> ---
>  drivers/cpufreq/scpi-cpufreq.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/cpufreq/scpi-cpufreq.c b/drivers/cpufreq/scpi-cpufreq.c
> index cd89c1b9832c..c888ed3a0de9 100644
> --- a/drivers/cpufreq/scpi-cpufreq.c
> +++ b/drivers/cpufreq/scpi-cpufreq.c
> @@ -30,6 +30,9 @@ static struct scpi_ops *scpi_ops;
>  static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
>  {
>  	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
> +	if (unlikely(!policy))
> +		return 0;
> +
>  	struct scpi_data *priv = policy->driver_data;
>  	unsigned long rate = clk_get_rate(priv->clk);
>  

-- 
Regards,
Sudeep

Re: [PATCH] cpufreq: scpi: Prevent null pointer dereference in scpi_cpufreq_get_rate()

Posted by Viresh Kumar 1 year, 4 months ago

On 30-12-24, 17:31, Charles Han wrote:
> cpufreq_cpu_get_raw() may return NULL if the cpu is not in
> policy->cpus cpu mask and it will cause null pointer dereference.
> Prevent null pointer dereference in scpi_cpufreq_get_rate().
> 
> Fixes: 343a8d17fa8d ("cpufreq: scpi: remove arm_big_little dependency")
> Signed-off-by: Charles Han <hanchunchao@inspur.com>
> ---
>  drivers/cpufreq/scpi-cpufreq.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/cpufreq/scpi-cpufreq.c b/drivers/cpufreq/scpi-cpufreq.c
> index cd89c1b9832c..c888ed3a0de9 100644
> --- a/drivers/cpufreq/scpi-cpufreq.c
> +++ b/drivers/cpufreq/scpi-cpufreq.c
> @@ -30,6 +30,9 @@ static struct scpi_ops *scpi_ops;
>  static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
>  {
>  	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
> +	if (unlikely(!policy))
> +		return 0;
> +
>  	struct scpi_data *priv = policy->driver_data;
>  	unsigned long rate = clk_get_rate(priv->clk);

The check needs to be made after all the variable definitions.

-- 
viresh