Hi Jinjie,
On Mon, 18 Sep 2023 15:47:58 +0800 Jinjie Ruan <ruanjinjie@xxxxxxxxxx> wrote:
> 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 use
> damon_free_region() to free it.
Nit. This patch is not directly adding use of damon_free_region() but replaces
damon_del_region() call with damon_destroy_region(), so that it calls both
damon_del_region() and damon_free_region().
I think this part might better to be re-written?
> 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@xxxxxxxxxx>
Other than the above trivial nit,
Reviewed-by: SeongJae Park <sj@xxxxxxxxxx>
> ---
> v2:
> - Replace the damon_del_region() with damon_destroy_region() rather than
> calling damon_free_region().
> - Update the commit message.
And thank you for making the changes.
Thanks,
SJ
> ---
> 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 79f1f12e0dd5..3959be35b901 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);
> @@ -321,6 +321,8 @@ 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)
> --
> 2.34.1
>
>
