When CONFIG_DAMON_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y and CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.
The damon_region which is allocated by kmem_cache_alloc() in damon_new_region() in damon_test_regions() and damon_test_update_monitoring_result() are not freed.
So for damon_test_regions(), replace damon_del_region() call with damon_destroy_region() so that it calls both damon_del_region() and damon_free_region(), the latter will free the damon_region. For damon_test_update_monitoring_result(), call damon_free_region() to free it. After applying this patch, the following memory leak is never detected.
unreferenced object 0xffff2b49c3edc000 (size 56): comm "kunit_try_catch", pid 338, jiffies 4294895280 (age 557.084s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 49 2b ff ff ............I+.. backtrace: [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368 [<00000000b528f67c>] kmem_cache_alloc+0x168/0x284 [<000000008603f022>] damon_new_region+0x28/0x54 [<00000000a3b8c64e>] damon_test_regions+0x38/0x270 [<00000000559c4801>] kunit_try_run_case+0x50/0xac [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c [<000000003c3e9211>] kthread+0x124/0x130 [<0000000028f85bdd>] ret_from_fork+0x10/0x20 unreferenced object 0xffff2b49c5b20000 (size 56): comm "kunit_try_catch", pid 354, jiffies 4294895304 (age 556.988s) hex dump (first 32 bytes): 03 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 96 00 00 00 49 2b ff ff ............I+.. backtrace: [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368 [<00000000b528f67c>] kmem_cache_alloc+0x168/0x284 [<000000008603f022>] damon_new_region+0x28/0x54 [<00000000ca019f80>] damon_test_update_monitoring_result+0x18/0x34 [<00000000559c4801>] kunit_try_run_case+0x50/0xac [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c [<000000003c3e9211>] kthread+0x124/0x130 [<0000000028f85bdd>] ret_from_fork+0x10/0x20
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Fixes: f4c978b6594b ("mm/damon/core-test: add a test for damon_update_monitoring_results()") Signed-off-by: Jinjie Ruan ruanjinjie@huawei.com Reviewed-by: SeongJae Park sj@kernel.org --- v3: - Update the commit message to be more accurate. - Add Reviewed-by. v2: - Replace the damon_del_region() with damon_destroy_region() rather than calling damon_free_region(). - Update the commit message. --- mm/damon/core-test.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h index 6cc8b245586d..28d24e698318 100644 --- a/mm/damon/core-test.h +++ b/mm/damon/core-test.h @@ -30,7 +30,7 @@ static void damon_test_regions(struct kunit *test) damon_add_region(r, t); KUNIT_EXPECT_EQ(test, 1u, damon_nr_regions(t));
- damon_del_region(r, t); + damon_destroy_region(r, t); KUNIT_EXPECT_EQ(test, 0u, damon_nr_regions(t));
damon_free_target(t); @@ -316,6 +316,8 @@ static void damon_test_update_monitoring_result(struct kunit *test) damon_update_monitoring_result(r, &old_attrs, &new_attrs); KUNIT_EXPECT_EQ(test, r->nr_accesses, 150); KUNIT_EXPECT_EQ(test, r->age, 20); + + damon_free_region(r); }
static void damon_test_set_attrs(struct kunit *test)