mm/damon/core: add damon_del_region() debug_sanity check

damon_del_region() should be called for targets that have one or more
regions.  Add a sanity check for that under CONFIG_DAMON_DEBUG_SANITY.

Link: https://lkml.kernel.org/r/20260306152914.86303-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 53b573b915c7004a70a295ef38e8b603db1f7748..c499a02ac44eb22dbe43423563b6d17c4efc47f5 100644 (file)
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -152,8 +152,21 @@ void damon_add_region(struct damon_region *r, struct damon_target *t)
        t->nr_regions++;
 }
 
+#ifdef CONFIG_DAMON_DEBUG_SANITY
+static void damon_verify_del_region(struct damon_target *t)
+{
+       WARN_ONCE(t->nr_regions == 0, "t->nr_regions == 0\n");
+}
+#else
+static void damon_verify_del_region(struct damon_target *t)
+{
+}
+#endif
+
 static void damon_del_region(struct damon_region *r, struct damon_target *t)
 {
+       damon_verify_del_region(t);
+
        list_del(&r->list);
        t->nr_regions--;
 }