linux-kernel - Re: [PATCH RESEND 2/2] mm/damon/core-test: Fix memory leak in damon_new

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Date:   Mon, 18 Sep 2023 13:38:11 +0800
From:   Feng Tang <feng.tang@...el.com>
To:     Jinjie Ruan <ruanjinjie@...wei.com>
CC:     <sj@...nel.org>, <akpm@...ux-foundation.org>,
        <brendan.higgins@...ux.dev>, <damon@...ts.linux.dev>,
        <linux-mm@...ck.org>, <kunit-dev@...glegroups.com>,
        <linux-kselftest@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND 2/2] mm/damon/core-test: Fix memory leak in
 damon_new_ctx()

On Mon, Sep 18, 2023 at 01:10:44PM +0800, Jinjie Ruan wrote:
> The damon_ctx which is allocated by kzalloc() in damon_new_ctx() in
> damon_test_ops_registration() and damon_test_set_attrs() are not freed and
> it causes below memory leak. So use damon_destroy_ctx() to free it.
> 
> unreferenced object 0xffff2b49c6968800 (size 512):
>   comm "kunit_try_catch", pid 350, jiffies 4294895294 (age 557.028s)
>   hex dump (first 32 bytes):
>     88 13 00 00 00 00 00 00 a0 86 01 00 00 00 00 00  ................
>     00 87 93 03 00 00 00 00 0a 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
>     [<0000000073acab3b>] __kmem_cache_alloc_node+0x174/0x290
>     [<00000000b5f89cef>] kmalloc_trace+0x40/0x164
>     [<00000000eb19e83f>] damon_new_ctx+0x28/0xb4
>     [<00000000daf6227b>] damon_test_ops_registration+0x34/0x328
>     [<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 0xffff2b49c1a9cc00 (size 512):
>   comm "kunit_try_catch", pid 356, jiffies 4294895306 (age 557.000s)
>   hex dump (first 32 bytes):
>     88 13 00 00 00 00 00 00 a0 86 01 00 00 00 00 00  ................
>     00 00 00 00 00 00 00 00 0a 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
>     [<0000000073acab3b>] __kmem_cache_alloc_node+0x174/0x290
>     [<00000000b5f89cef>] kmalloc_trace+0x40/0x164
>     [<00000000eb19e83f>] damon_new_ctx+0x28/0xb4
>     [<00000000058495c4>] damon_test_set_attrs+0x30/0x1a8
>     [<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: d1836a3b2a9a ("mm/damon/core-test: initialise context before test in damon_test_set_attrs()")

Thanks for the fix!

Reviewed-by: Feng Tang <feng.tang@...el.com>

> Fixes: 4f540f5ab4f2 ("mm/damon/core-test: add a kunit test case for ops registration")
> Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
> ---
>  mm/damon/core-test.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
> index 255f8c925c00..ce86ed30fb47 100644
> --- a/mm/damon/core-test.h
> +++ b/mm/damon/core-test.h
> @@ -266,6 +266,8 @@ static void damon_test_ops_registration(struct kunit *test)
>  
>  	/* Check double-registration failure again */
>  	KUNIT_EXPECT_EQ(test, damon_register_ops(&ops), -EINVAL);
> +
> +	damon_destroy_ctx(c);
>  }
>  
>  static void damon_test_set_regions(struct kunit *test)
> @@ -342,6 +344,8 @@ static void damon_test_set_attrs(struct kunit *test)
>  	invalid_attrs = valid_attrs;
>  	invalid_attrs.aggr_interval = 4999;
>  	KUNIT_EXPECT_EQ(test, damon_set_attrs(c, &invalid_attrs), -EINVAL);
> +
> +	damon_destroy_ctx(c);
>  }
>  
>  static void damos_test_new_filter(struct kunit *test)
> -- 
> 2.34.1
>