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

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

[SeongJae Park]

damon_test_set_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/20251101182021.74868-11-sj@kernel.org
Fixes: 62f409560eb2 ("mm/damon/core-test: test damon_set_regions")
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>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 74d5969995d129fd59dd93b9c7daa6669cb6810f)
---
 mm/damon/core-test.h | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
index 6cc8b245586d..6629407cf986 100644
--- a/mm/damon/core-test.h
+++ b/mm/damon/core-test.h
@@ -270,13 +270,26 @@ static void damon_test_ops_registration(struct kunit *test)
 static void damon_test_set_regions(struct kunit *test)
 {
 	struct damon_target *t = damon_new_target();
-	struct damon_region *r1 = damon_new_region(4, 16);
-	struct damon_region *r2 = damon_new_region(24, 32);
+	struct damon_region *r1, *r2;
 	struct damon_addr_range range = {.start = 8, .end = 28};
 	unsigned long expects[] = {8, 16, 16, 24, 24, 28};
 	int expect_idx = 0;
 	struct damon_region *r;
 
+	if (!t)
+		kunit_skip(test, "target alloc fail");
+	r1 = damon_new_region(4, 16);
+	if (!r1) {
+		damon_free_target(t);
+		kunit_skip(test, "region alloc fail");
+	}
+	r2 = damon_new_region(24, 32);
+	if (!r2) {
+		damon_free_target(t);
+		damon_free_region(r1);
+		kunit_skip(test, "second region alloc fail");
+	}
+
 	damon_add_region(r1, t);
 	damon_add_region(r2, t);
 	damon_set_regions(t, &range, 1);
-- 
2.47.3