From: Rafael J. Wysocki rafael.j.wysocki@intel.com
commit 935dff305da2be7957a5ce8f07f45d6c4c1c6984 upstream.
Check cpc_desc against NULL in cppc_get_perf(), so it doesn't crash down the road if cpc_desc is NULL.
Fixes: 0654cf05d17b ("ACPI: CPPC: Introduce cppc_get_nominal_perf()") Reported-by: Kai-Heng Feng kai.heng.feng@canonical.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc: 5.15+ stable@vger.kernel.org # 5.15+ Tested-by: Kai-Heng Feng kai.heng.feng@canonical.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/cppc_acpi.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1011,7 +1011,14 @@ static int cpc_write(int cpu, struct cpc static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf) { struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum); - struct cpc_register_resource *reg = &cpc_desc->cpc_regs[reg_idx]; + struct cpc_register_resource *reg; + + if (!cpc_desc) { + pr_debug("No CPC descriptor for CPU:%d\n", cpunum); + return -ENODEV; + } + + reg = &cpc_desc->cpc_regs[reg_idx];
if (CPC_IN_PCC(reg)) { int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);