6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/c4765377-7830-44c2-84fa-706b6e304e10@stanley.mountain/
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
Suggested-by: Quentin Perret <qperret@xxxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 975fb9fa23cac..2993b8a4c7f17 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -494,7 +494,7 @@ 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;
--
2.43.0
