On Mon, Dec 04, 2017 at 02:06:54PM +0000, George Cherian wrote:
> Default value of pcc_subspace_idx is -1.
> Make sure to check pcc_subspace_idx before using the same as array index.
> This will avoid following KASAN warnings too.
> @@ -1172,11 +1174,12 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls
> *perf_ctrls)
> struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
I think you forgot to remove this initialization. Coverity reported this:
*** CID 1426090: Memory - illegal accesses (REVERSE_NEGATIVE)
/drivers/acpi/cppc_acpi.c: 1177 in cppc_set_perf()
1171 struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1172 struct cpc_register_resource *desired_reg;
1173 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1174 struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
1175 int ret = 0;
1176
>>> CID 1426090: Memory - illegal accesses (REVERSE_NEGATIVE)
>>> You might be using variable "pcc_ss_id" before verifying that it is
>= 0.
1177 if (!cpc_desc || pcc_ss_id < 0) {
1178 pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1179 return -ENODEV;
1180 }
1181
1182 pcc_ss_data = pcc_data[pcc_ss_id];
> int ret = 0;
>
> - if (!cpc_desc) {
> + if (!cpc_desc || pcc_ss_id < 0) {
> pr_debug("No CPC descriptor for CPU:%d\n", cpu);
> return -ENODEV;
> }
>
> + pcc_ss_data = pcc_data[pcc_ss_id];
> desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
>
> /*
