[PATCH 5.15.y] mm/damon/tests/core-kunit: handle alloc failures on dasmon_test_merge_regions_of()

[SeongJae Park <sj@kernel.org>]

damon_test_merge_regions_of() is assuming all dynamic memory allocation in
it will succeed.  Those are indeed likely in the real use cases since
those allocations are too small to fail, but theoretically those could
fail.  In the case, inappropriate memory access can happen.  Fix it by
appropriately cleanup pre-allocated memory and skip the execution of the
remaining tests in the failure cases.

Link: https://lkml.kernel.org/r/20251101182021.74868-8-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org>	[5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 0998d2757218771c59d5ca59ccf13d1542a38f17)
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core-test.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
index 7008c3735e99..92539b6aeb65 100644
--- a/mm/damon/core-test.h
+++ b/mm/damon/core-test.h
@@ -192,8 +192,14 @@ static void damon_test_merge_regions_of(struct kunit *test)
 	int i;
 
 	t = damon_new_target(42);
+	if (!t)
+		kunit_skip(test, "target alloc fail");
 	for (i = 0; i < ARRAY_SIZE(sa); i++) {
 		r = damon_new_region(sa[i], ea[i]);
+		if (!r) {
+			damon_free_target(t);
+			kunit_skip(test, "region alloc fail");
+		}
 		r->nr_accesses = nrs[i];
 		damon_add_region(r, t);
 	}
-- 
2.47.3