[6.1,1/1] cpufreq: amd-pstate: add check for cpufreq_cpu_get's return value

Commit Message

Anastasia Belova Nov. 6, 2024, 1:24 p.m. UTC

From: Anastasia Belova <[e-mail]>

commit 5493f9714e4cdaf0ee7cec15899a231400cb1a9f upstream.

cpufreq_cpu_get may return NULL. To avoid NULL-dereference check it
and return in case of error.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Anastasia Belova <[e-mail]>
Reviewed-by: Perry Yuan <[e-mail]>
Signed-off-by: Viresh Kumar <[e-mail]>
---
 drivers/cpufreq/amd-pstate.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Anastasia Belova Nov. 6, 2024, 5:57 p.m. UTC | #1

Hi!

I found out this commit should be backported to 6.6 first.
Should I resend this letter after it is done or I may ping it later?

Anastasia Belova

Yuan, Perry Nov. 7, 2024, 3:02 a.m. UTC | #2

[AMD Official Use Only - AMD Internal Distribution Only]

> -----Original Message-----
> From: Anastasia Belova <[e-mail]>
> Sent: Thursday, November 7, 2024 1:57 AM
> To: [e-mail]; Greg Kroah-Hartman <[e-mail]>
> Cc: [e-mail]; Huang, Ray <[e-mail]>; Rafael J.
> Wysocki <[e-mail]>; Viresh Kumar <[e-mail]>; linux-
> [e-mail]; [e-mail]; Yuan, Perry
> <[e-mail]>
> Subject: Re: [PATCH 6.1 1/1] cpufreq: amd-pstate: add check for cpufreq_cpu_get's
> return value
>
> Hi!
>
> I found out this commit should be backported to 6.6 first.
> Should I resend this letter after it is done or I may ping it later?
>
> Anastasia Belova


+ Mario and Gautham for help.

Best Regards.

Perry.

Patch

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 90dcf26f0973..106aef210003 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -309,9 +309,14 @@  static void amd_pstate_adjust_perf(unsigned int cpu,
 	unsigned long max_perf, min_perf, des_perf,
 		      cap_perf, lowest_nonlinear_perf, max_freq;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-	struct amd_cpudata *cpudata = policy->driver_data;
+	struct amd_cpudata *cpudata;
 	unsigned int target_freq;
 
+	if (!policy)
+		return;
+
+	cpudata = policy->driver_data;
+
 	cap_perf = READ_ONCE(cpudata->highest_perf);
 	lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
 	max_freq = READ_ONCE(cpudata->max_freq);