mm/damon/tests/vaddr-kunit: handle alloc failures on damon_test_split_evenly_succ()

damon_test_split_evenly_succ() 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/20251101182021.74868-20-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>

diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
index 1b0f21c..30dc545 100644 (file)
--- a/mm/damon/tests/vaddr-kunit.h
+++ b/mm/damon/tests/vaddr-kunit.h
@@ -284,10 +284,17 @@ static void damon_test_split_evenly_succ(struct kunit *test,
        unsigned long start, unsigned long end, unsigned int nr_pieces)
 {
        struct damon_target *t = damon_new_target();
-       struct damon_region *r = damon_new_region(start, end);
+       struct damon_region *r;
        unsigned long expected_width = (end - start) / nr_pieces;
        unsigned long i = 0;
 
+       if (!t)
+               kunit_skip(test, "target alloc fail");
+       r = damon_new_region(start, end);
+       if (!r) {
+               damon_free_target(t);
+               kunit_skip(test, "region alloc fail");
+       }
        damon_add_region(r, t);
        KUNIT_EXPECT_EQ(test,
                        damon_va_evenly_split_region(t, r, nr_pieces), 0);