* [PATCH] ACPI / CPPC: remove initial assignment of pcc_ss_data
@ 2017-12-08 23:59 Colin King
2017-12-16 1:49 ` Rafael J. Wysocki
0 siblings, 1 reply; 2+ messages in thread
From: Colin King @ 2017-12-08 23:59 UTC (permalink / raw)
To: Rafael J . Wysocki, Len Brown, linux-acpi; +Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The initialization of pcc_ss_data from pcc_data[pcc_ss_id] before
pcc_ss_id is being range checked could lead to an out-of-bounds array
read. This very same initialization is also being performed after
the range check on pcc_ss_id, so we can just remove this problematic
and also redundant assignment to fix the issue.
Detected by cppcheck:
warning: Value stored to 'pcc_ss_data' during its initialization is never
read
Fixes: commit 85b1407bf6d2 ("ACPI / CPPC: Make CPPC ACPI driver aware of PCC subspace IDs")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/acpi/cppc_acpi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 30e84cc600ae..06ea4749ebd9 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1171,7 +1171,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
struct cpc_register_resource *desired_reg;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
- struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
+ struct cppc_pcc_data *pcc_ss_data;
int ret = 0;
if (!cpc_desc || pcc_ss_id < 0) {
--
2.14.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ACPI / CPPC: remove initial assignment of pcc_ss_data
2017-12-08 23:59 [PATCH] ACPI / CPPC: remove initial assignment of pcc_ss_data Colin King
@ 2017-12-16 1:49 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2017-12-16 1:49 UTC (permalink / raw)
To: Colin King; +Cc: Len Brown, linux-acpi, kernel-janitors, linux-kernel
On Saturday, December 9, 2017 12:59:49 AM CET Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The initialization of pcc_ss_data from pcc_data[pcc_ss_id] before
> pcc_ss_id is being range checked could lead to an out-of-bounds array
> read. This very same initialization is also being performed after
> the range check on pcc_ss_id, so we can just remove this problematic
> and also redundant assignment to fix the issue.
>
> Detected by cppcheck:
> warning: Value stored to 'pcc_ss_data' during its initialization is never
> read
>
> Fixes: commit 85b1407bf6d2 ("ACPI / CPPC: Make CPPC ACPI driver aware of PCC subspace IDs")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/acpi/cppc_acpi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 30e84cc600ae..06ea4749ebd9 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1171,7 +1171,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
> struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
> struct cpc_register_resource *desired_reg;
> int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
> - struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
> + struct cppc_pcc_data *pcc_ss_data;
> int ret = 0;
>
> if (!cpc_desc || pcc_ss_id < 0) {
>
Applied, thanks!
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