6.6-stable review patch. If anyone has any objections, please let me know.
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From: Aleksandr Mishin amishin@t-argos.ru
[ 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@t-argos.ru Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 fe08ca419b3dc..1ba3943be8a3d 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -844,10 +844,15 @@ 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); @@ -927,10 +932,15 @@ 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);