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 1b0f21c2e37630801f6d1bd712538e5b60870cd7..30dc5459f1d2c058c73f8f927c49853132bdcd11 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);