2021-11-18 13:33:24

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH] ACPI: CPPC: Add NULL pointer check to cppc_get_perf()

From: Rafael J. Wysocki <[email protected]>

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 <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Cc: 5.15+ <[email protected]> # 5.15+
---
drivers/acpi/cppc_acpi.c | 5 +++++
1 file changed, 5 insertions(+)

Index: linux-pm/drivers/acpi/cppc_acpi.c
===================================================================
--- linux-pm.orig/drivers/acpi/cppc_acpi.c
+++ linux-pm/drivers/acpi/cppc_acpi.c
@@ -1000,6 +1000,11 @@ static int cppc_get_perf(int cpunum, enu
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
struct cpc_register_resource *reg = &cpc_desc->cpc_regs[reg_idx];

+ if (!cpc_desc) {
+ pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
+ return -ENODEV;
+ }
+
if (CPC_IN_PCC(reg)) {
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
struct cppc_pcc_data *pcc_ss_data = NULL;





2021-11-18 13:37:43

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH v2] ACPI: CPPC: Add NULL pointer check to cppc_get_perf()

From: Rafael J. Wysocki <[email protected]>
Subject: [PATCH] ACPI: CPPC: Add NULL pointer check to cppc_get_perf()

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 <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Cc: 5.15+ <[email protected]> # 5.15+
---

-> v2: Check cpc_desc against NULL before using it to initialize reg.

---
drivers/acpi/cppc_acpi.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/cppc_acpi.c
===================================================================
--- linux-pm.orig/drivers/acpi/cppc_acpi.c
+++ linux-pm/drivers/acpi/cppc_acpi.c
@@ -998,7 +998,14 @@ 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);




2021-11-24 07:46:51

by Kai-Heng Feng

[permalink] [raw]
Subject: Re: [PATCH v2] ACPI: CPPC: Add NULL pointer check to cppc_get_perf()

On Thu, Nov 18, 2021 at 9:37 PM Rafael J. Wysocki <[email protected]> wrote:
>
> From: Rafael J. Wysocki <[email protected]>
> Subject: [PATCH] ACPI: CPPC: Add NULL pointer check to cppc_get_perf()
>
> 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 <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> Cc: 5.15+ <[email protected]> # 5.15+

Sorry for the late test, I bricked my previous ADL rig.
Tested-by: Kai-Heng Feng <[email protected]>

> ---
>
> -> v2: Check cpc_desc against NULL before using it to initialize reg.
>
> ---
> drivers/acpi/cppc_acpi.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> Index: linux-pm/drivers/acpi/cppc_acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/cppc_acpi.c
> +++ linux-pm/drivers/acpi/cppc_acpi.c
> @@ -998,7 +998,14 @@ 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);
>
>
>