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[4/4,Bionic,SRU,Artful] ACPI: CPPC: remove initial assignment of pcc_ss_data

Message ID 20180123192947.22399-5-dann.frazier@canonical.com
State New
Headers show
Series None | expand

Commit Message

dann frazier Jan. 23, 2018, 7:29 p.m. UTC 
From: Colin Ian King <colin.king@canonical.com>

BugLink: https://bugs.launchpad.net/bugs/1745007

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: 85b1407bf6d2 (ACPI / CPPC: Make CPPC ACPI driver aware of PCC subspace IDs)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 951ef0e19f0736b45d1c4d81f4dfa04a43f87df5)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
---
 drivers/acpi/cppc_acpi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

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) {