Hi Jinjie,
Thank you for this patchset!
On Mon, 18 Sep 2023 13:10:43 +0800 Jinjie Ruan ruanjinjie@huawei.com wrote:
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 and it causes below memory leak. So use damon_free_region() to free it.
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
Nice finding! Could you please share just a brief more detail about above cool output, e.g., just the name of the tool you used, so that others can learn it from your awesome commit message?
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
mm/damon/core-test.h | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h index 6cc8b245586d..255f8c925c00 100644 --- a/mm/damon/core-test.h +++ b/mm/damon/core-test.h @@ -34,6 +34,7 @@ static void damon_test_regions(struct kunit *test) KUNIT_EXPECT_EQ(test, 0u, damon_nr_regions(t)); damon_free_target(t);
- damon_free_region(r);
There is damon_destroy_region() function, which simply calls damon_del_region() and damon_free_region(). Unless there is needs to access the region before removing from the region, doing memory return together via the function is recommended.
And this test code calls damon_del_region() just beofre above KUNIT_EXPECT_EQ(). Hence, I think replacing the damon_del_region() call with damon_destroy_region() rather than calling damon_free_region() may be simpler and shorter. Could you please do so?
} static unsigned int nr_damon_targets(struct damon_ctx *ctx) @@ -316,6 +317,8 @@ 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);
This looks nice. Thank you for fixing this!
} static void damon_test_set_attrs(struct kunit *test) -- 2.34.1
Thanks, SJ