mm/damon/tests/core-kunit: handle allocation failures in damon_test_regions()

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>

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 69ca44f9270bbe5e4b51b39f432123cf839a5e57..a2c9ee7a5de1a7af39d2dd8ed2f7c1ffe773d1d0 100644 (file)
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.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);