[PATCH sched_ext/for-7.2-fixes] sched_ext: Annotate ksyncs with __rcu in alloc/free_kick_syncs()

[PATCH sched_ext/for-7.2-fixes] sched_ext: Annotate ksyncs with __rcu in alloc/free_kick_syncs()

[Tejun Heo]

scx_kick_syncs is a per-CPU __rcu pointer, so per_cpu_ptr() returns struct
scx_kick_syncs __rcu **. alloc_kick_syncs() and free_kick_syncs() stored it
in a plain struct scx_kick_syncs **ksyncs, which sparse flags as an __rcu
address-space mismatch. Annotate ksyncs to match. Its accesses already go
through rcu_*_pointer().

Fixes: 987e00035c0e ("sched_ext: Rename pnt_seq to kick_sync")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202606122315.pbnDHP0n-lkp@intel.com/
Signed-off-by: Tejun Heo <tj@kernel.org>
---
 kernel/sched/ext/ext.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
index e353204b4ca2..9c9cb9d08bca 100644
--- a/kernel/sched/ext/ext.c
+++ b/kernel/sched/ext/ext.c
@@ -5730,7 +5730,7 @@ static void free_kick_syncs(void)
 	int cpu;
 
 	for_each_possible_cpu(cpu) {
-		struct scx_kick_syncs **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
+		struct scx_kick_syncs __rcu **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
 		struct scx_kick_syncs *to_free;
 
 		to_free = rcu_replace_pointer(*ksyncs, NULL, true);
@@ -6720,7 +6720,7 @@ static int alloc_kick_syncs(void)
 	 * can exceed percpu allocator limits on large machines.
 	 */
 	for_each_possible_cpu(cpu) {
-		struct scx_kick_syncs **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
+		struct scx_kick_syncs __rcu **ksyncs = per_cpu_ptr(&scx_kick_syncs, cpu);
 		struct scx_kick_syncs *new_ksyncs;
 
 		WARN_ON_ONCE(rcu_access_pointer(*ksyncs));

Re: [PATCH sched_ext/for-7.2-fixes] sched_ext: Annotate ksyncs with __rcu in alloc/free_kick_syncs()

[Tejun Heo]

Applied to sched_ext/for-7.2-fixes.

Thanks.

--
tejun