[PATCH v3 4/4] arch_topology: Free raw_capacity when topology parsing fails

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

When parsing /cpus/cpu-map fails in parse_dt_topology(),
init_cpu_topology() calls reset_cpu_topology() without calling
free_raw_capacity().

topology_parse_cpu_capacity() allocates raw_capacity on the first CPU
node with a capacity-dmips-mhz property. If a subsequent core, cluster
or socket fails to parse in parse_socket(), or if a possible CPU is
missing from cpu-map, raw_capacity is left allocated and partially
populated.

With CONFIG_CPU_FREQ=y, free_raw_capacity() is not registered as an
initcall. If cpufreq policies are registered for all possible CPUs,
init_cpu_capacity_callback() sees the non-NULL raw_capacity pointer and
runs topology_normalize_cpu_scale() on the incomplete array, leaving
unparsed CPUs with a capacity scale of 0; otherwise, raw_capacity is
leaked.

Free raw_capacity when init_cpu_topology() resets the topology on
parsing failure to discard the partial capacity data and avoid leaking
memory or setting unparsed CPUs to capacity 0.

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 | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index c439fc91270d..7783c0c517eb 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -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