mm/damon/tests/core-kunit: handle alloc failres in damon_test_new_filter()

commit 28ab226 upstream.

damon_test_new_filter() 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/20251101182021.74868-14-sj@kernel.org
Fixes: 2a158e9 ("mm/damon/core-test: add a test for damos_new_filter()")
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>	[6.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: sjp38

mm/damon/tests/core-kunit.h

@@ -505,6 +505,8 @@ static void damos_test_new_filter(struct kunit *test)
 	struct damos_filter *filter;
 
 	filter = damos_new_filter(DAMOS_FILTER_TYPE_ANON, true);
+	if (!filter)
+		kunit_skip(test, "filter alloc fail");
 	KUNIT_EXPECT_EQ(test, filter->type, DAMOS_FILTER_TYPE_ANON);
 	KUNIT_EXPECT_EQ(test, filter->matching, true);
 	KUNIT_EXPECT_PTR_EQ(test, filter->list.prev, &filter->list);