[PATCH v2 1/3] sched/topology: Annotate RCU pointers properly

From: Pierre Gondois
Date: Mon Jan 15 2024 - 09:34:59 EST


Cleanup RCU-related spare errors by annotating RCU pointers.

sched_domains_numa_distance:
error: incompatible types in comparison expression
(different address spaces):
int [noderef] __rcu *
int *

sched_domains_numa_masks:
error: incompatible types in comparison expression
(different address spaces):
struct cpumask **[noderef] __rcu *
struct cpumask ***

The cast to (void *) adds the following sparse warning:
warning: cast removes address space '__rcu' of expression
but this should be normal.

Fixes: 0fb3978b0aac ("sched/numa: Fix NUMA topology for systems with CPU-less nodes")
Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
---
kernel/sched/topology.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 10d1391e7416..2a2da9b33e31 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1542,8 +1542,8 @@ static int sched_domains_numa_levels;
static int sched_domains_curr_level;

int sched_max_numa_distance;
-static int *sched_domains_numa_distance;
-static struct cpumask ***sched_domains_numa_masks;
+static int __rcu *sched_domains_numa_distance;
+static struct cpumask ** __rcu *sched_domains_numa_masks;
#endif

/*
@@ -1988,8 +1988,8 @@ void sched_init_numa(int offline_node)

static void sched_reset_numa(void)
{
- int nr_levels, *distances;
- struct cpumask ***masks;
+ int nr_levels, __rcu *distances;
+ struct cpumask ** __rcu *masks;

nr_levels = sched_domains_numa_levels;
sched_domains_numa_levels = 0;
@@ -2003,7 +2003,7 @@ static void sched_reset_numa(void)
int i, j;

synchronize_rcu();
- kfree(distances);
+ kfree((void *)distances);
for (i = 0; i < nr_levels && masks; i++) {
if (!masks[i])
continue;
@@ -2011,7 +2011,7 @@ static void sched_reset_numa(void)
kfree(masks[i][j]);
kfree(masks[i]);
}
- kfree(masks);
+ kfree((void *)masks);
}
if (sched_domain_topology_saved) {
kfree(sched_domain_topology);
--
2.25.1