2023-09-18 08:08:26

by Jinjie Ruan

Subject: [PATCH v2 1/2] mm/damon/core-test: Fix memory leak in damon_new_region()

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. 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 <[email protected]>
---
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 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

2023-09-18 11:35:22

by SeongJae Park

Subject: Re: [PATCH v2 1/2] mm/damon/core-test: Fix memory leak in damon_new_region()

Hi Jinjie,

On Mon, 18 Sep 2023 15:47:58 +0800 Jinjie Ruan <[email protected]> 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 <[email protected]>

Other than the above trivial nit,

Reviewed-by: SeongJae Park <[email protected]>

> ---
> 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
>
>

2023-09-18 11:44:22

by Jinjie Ruan

Subject: Re: [PATCH v2 1/2] mm/damon/core-test: Fix memory leak in damon_new_region()

On 2023/9/18 19:00, SeongJae Park wrote:
> Hi Jinjie,
>
> On Mon, 18 Sep 2023 15:47:58 +0800 Jinjie Ruan <[email protected]> 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?

OK. Thank you!

>
>> 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 <[email protected]>
>
> Other than the above trivial nit,
>
> Reviewed-by: SeongJae Park <[email protected]>
>
>> ---
>> 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
>>
>>