[PATCH 6.6.y] mm/damon/tests/core-kunit: handle allocation failures in damon_test_regions()

[SeongJae Park <sj@kernel.org>]

damon_test_regions() 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/20251101182021.74868-3-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 e16fdd4f754048d6e23c56bd8d920b71e41e3777)
---
 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 6cc8b245586d..23a6d3ae9aed 100644
--- a/mm/damon/core-test.h
+++ b/mm/damon/core-test.h
@@ -20,11 +20,17 @@ static void damon_test_regions(struct kunit *test)
 	struct damon_target *t;
 
 	r = damon_new_region(1, 2);
+	if (!r)
+		kunit_skip(test, "region alloc fail");
 	KUNIT_EXPECT_EQ(test, 1ul, r->ar.start);
 	KUNIT_EXPECT_EQ(test, 2ul, r->ar.end);
 	KUNIT_EXPECT_EQ(test, 0u, r->nr_accesses);
 
 	t = damon_new_target();
+	if (!t) {
+		damon_free_region(r);
+		kunit_skip(test, "target alloc fail");
+	}
 	KUNIT_EXPECT_EQ(test, 0u, damon_nr_regions(t));
 
 	damon_add_region(r, t);
-- 
2.47.3