* [PATCH][next] cpufreq: powernow-k8: add null check to policy to avoid null pointer dereference
@ 2021-01-04 13:02 ` Colin King
0 siblings, 0 replies; 4+ messages in thread
From: Colin King @ 2021-01-04 13:02 UTC (permalink / raw
To: Rafael J . Wysocki, Viresh Kumar, Stephen Warren, linux-pm
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Currently there is an unlikely case where cpufreq_cpu_get returns a
null policy and this will cause a null pointer dereference later on.
Fix this by adding a null check and adding an error return.
Addresses-Coverity: ("Dereference null return")
Fixes: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/cpufreq/powernow-k8.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 0acc9e241cd7..c5368545ba1f 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -913,6 +913,8 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
freqs.new = find_khz_freq_from_fid(fid);
policy = cpufreq_cpu_get(smp_processor_id());
+ if (!policy)
+ return 1;
cpufreq_cpu_put(policy);
cpufreq_freq_transition_begin(policy, &freqs);
--
2.29.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH][next] cpufreq: powernow-k8: add null check to policy to avoid null pointer dereference
@ 2021-01-04 13:02 ` Colin King
0 siblings, 0 replies; 4+ messages in thread
From: Colin King @ 2021-01-04 13:02 UTC (permalink / raw
To: Rafael J . Wysocki, Viresh Kumar, Stephen Warren, linux-pm
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Currently there is an unlikely case where cpufreq_cpu_get returns a
null policy and this will cause a null pointer dereference later on.
Fix this by adding a null check and adding an error return.
Addresses-Coverity: ("Dereference null return")
Fixes: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/cpufreq/powernow-k8.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 0acc9e241cd7..c5368545ba1f 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -913,6 +913,8 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
freqs.new = find_khz_freq_from_fid(fid);
policy = cpufreq_cpu_get(smp_processor_id());
+ if (!policy)
+ return 1;
cpufreq_cpu_put(policy);
cpufreq_freq_transition_begin(policy, &freqs);
--
2.29.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH][next] cpufreq: powernow-k8: add null check to policy to avoid null pointer dereference
2021-01-04 13:02 ` Colin King
@ 2021-01-05 3:55 ` Viresh Kumar
-1 siblings, 0 replies; 4+ messages in thread
From: Viresh Kumar @ 2021-01-05 3:54 UTC (permalink / raw
To: Colin King
Cc: Rafael J . Wysocki, Stephen Warren, linux-pm, kernel-janitors,
linux-kernel
On 04-01-21, 13:02, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently there is an unlikely case where cpufreq_cpu_get returns a
> null policy and this will cause a null pointer dereference later on.
> Fix this by adding a null check and adding an error return.
>
> Addresses-Coverity: ("Dereference null return")
> Fixes: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/cpufreq/powernow-k8.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
> index 0acc9e241cd7..c5368545ba1f 100644
> --- a/drivers/cpufreq/powernow-k8.c
> +++ b/drivers/cpufreq/powernow-k8.c
> @@ -913,6 +913,8 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
The caller already has a pointer to the policy, you should rather pass
that here instead of doing cpufreq_cpu_get/put.
> freqs.new = find_khz_freq_from_fid(fid);
>
> policy = cpufreq_cpu_get(smp_processor_id());
> + if (!policy)
> + return 1;
> cpufreq_cpu_put(policy);
>
> cpufreq_freq_transition_begin(policy, &freqs);
> --
> 2.29.2
--
viresh
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH][next] cpufreq: powernow-k8: add null check to policy to avoid null pointer dereference
@ 2021-01-05 3:55 ` Viresh Kumar
0 siblings, 0 replies; 4+ messages in thread
From: Viresh Kumar @ 2021-01-05 3:55 UTC (permalink / raw
To: Colin King
Cc: Rafael J . Wysocki, Stephen Warren, linux-pm, kernel-janitors,
linux-kernel
On 04-01-21, 13:02, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently there is an unlikely case where cpufreq_cpu_get returns a
> null policy and this will cause a null pointer dereference later on.
> Fix this by adding a null check and adding an error return.
>
> Addresses-Coverity: ("Dereference null return")
> Fixes: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/cpufreq/powernow-k8.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
> index 0acc9e241cd7..c5368545ba1f 100644
> --- a/drivers/cpufreq/powernow-k8.c
> +++ b/drivers/cpufreq/powernow-k8.c
> @@ -913,6 +913,8 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
The caller already has a pointer to the policy, you should rather pass
that here instead of doing cpufreq_cpu_get/put.
> freqs.new = find_khz_freq_from_fid(fid);
>
> policy = cpufreq_cpu_get(smp_processor_id());
> + if (!policy)
> + return 1;
> cpufreq_cpu_put(policy);
>
> cpufreq_freq_transition_begin(policy, &freqs);
> --
> 2.29.2
--
viresh
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-01-04 13:02 [PATCH][next] cpufreq: powernow-k8: add null check to policy to avoid null pointer dereference Colin King
2021-01-04 13:02 ` Colin King
2021-01-05 3:54 ` Viresh Kumar
2021-01-05 3:55 ` Viresh Kumar
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