[PATCH v4 4/4] arch_topology: Avoid zero CPU capacity on parse failure

[Sudeep Holla <sudeep.holla@kernel.org>]

When a possible CPU is missing from cpu-map, parse_dt_topology()
normalizes the partially populated raw_capacity array before checking
that all possible CPUs are represented. This leaves the missing CPU with
a capacity of 0.

Validate all possible CPUs before normalizing capacities so parse
failures do not write partial values to cpu_scale. Free raw_capacity on
the failure path to discard partial data and avoid a leak.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/bug/linux-1a2a8094-971d-40cb-b0cf-2e6d9f26c549
Fixes: 60c1b220d8bc ("cpu-topology: Move cpu topology code to common code.")
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
 drivers/base/arch_topology.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index c439fc91270d..e868b7de88fa 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -682,8 +682,6 @@ static int __init parse_dt_topology(void)
 	if (ret != 0)
 		return ret;
 
-	topology_normalize_cpu_scale();
-
 	/*
 	 * Check that all cores are in the topology; the SMP code will
 	 * only mark cores described in the DT as possible.
@@ -693,6 +691,8 @@ static int __init parse_dt_topology(void)
 			return -EINVAL;
 		}
 
+	topology_normalize_cpu_scale();
+
 	return ret;
 }
 #endif
@@ -954,6 +954,7 @@ void __init init_cpu_topology(void)
 		 * arch-specific early cache level detection a chance to run.
 		 */
 		reset_cpu_topology();
+		free_raw_capacity();
 		cpu_smt_set_num_threads(1, 1);
 	}
 
-- 
2.43.0