6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jinjie Ruan ruanjinjie@huawei.com
[ Upstream commit be392aa80f1e5b0b65ccc2a540b9304fefcfe3d8 ]
cppc_get_cpu_cost() return 0 if the policy is NULL. Then in em_compute_costs(), the later zero check for cost is not valid as cost is uninitialized. As Quentin pointed out, kernel energy model core check the return value of get_cost() first, so if the callback failed it should tell the core. Return -EINVAL to fix it.
Fixes: 1a1374bb8c59 ("cpufreq: CPPC: Fix possible null-ptr-deref for cppc_get_cpu_cost()") Reported-by: Dan Carpenter dan.carpenter@linaro.org Closes: https://lore.kernel.org/all/c4765377-7830-44c2-84fa-706b6e304e10@stanley.mou... Signed-off-by: Jinjie Ruan ruanjinjie@huawei.com Suggested-by: Quentin Perret qperret@google.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/cppc_cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index 866a0538ca896..05a8418485079 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -499,7 +499,7 @@ static int cppc_get_cpu_cost(struct device *cpu_dev, unsigned long KHz,
policy = cpufreq_cpu_get_raw(cpu_dev->id); if (!policy) - return 0; + return -EINVAL;
cpu_data = policy->driver_data; perf_caps = &cpu_data->perf_caps;