linux-kernel - Re: [PATCH bpf] selftests/bpf: Fix resource leak in serial_test

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Message-ID: <3b4f4404-0298-4f9d-a6ba-e8b2f125818d@linux.dev>
Date: Wed, 21 Jan 2026 15:05:32 -0800
From: Yonghong Song <yonghong.song@...ux.dev>
To: Kery Qi <qikeyu2017@...il.com>
Cc: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
 shuah@...nel.org, martin.lau@...ux.dev, eddyz87@...il.com, song@...nel.org,
 john.fastabend@...il.com, kpsingh@...nel.org, sdf@...ichev.me,
 haoluo@...gle.com, jolsa@...nel.org, yatsenko@...a.com, bentiss@...nel.org,
 bpf@...r.kernel.org, linux-kselftest@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH bpf] selftests/bpf: Fix resource leak in serial_test_wq on
 attach failure



On 1/21/26 9:49 AM, Kery Qi wrote:
> Hi,
>
> Thank you for the review.
>
> You are completely right regarding wq__open_and_load(): if it fails,
> it returns NULL and performs its own cleanup, so an immediate return
> is correct there.
>
> However, my concern is about the next step: wq__attach(wq_skel).
>
> If wq__open_and_load() succeeds, wq_skel is allocated. If wq__attach()
> subsequently fails, the original code returns immediately without
> calling wq__destroy(wq_skel), which causes a memory leak of the
> skeleton object.
>
> The proposed goto clean_up is intended to ensure wq__destroy(wq_skel)
> is called specifically when wq__attach() fails.
>
> Does that make sense?

Yes.

>
> Best regards,
>
> Kery
>
> Yonghong Song <yonghong.song@...ux.dev> 于2026年1月21日周三 23:45写道：
>>
>>
>> On 1/21/26 1:41 AM, Kery Qi wrote:
>>> When wq__attach() fails, serial_test_wq() returns early without calling
>>> wq__destroy(), leaking the skeleton resources allocated by
>>> wq__open_and_load(). This causes ASAN leak reports in selftests runs.
>>>
>>> Fix this by jumping to a common clean_up label that calls wq__destroy()
>>> on all exit paths after successful open_and_load.
>>>
>>> Note that the early return after wq__open_and_load() failure is correct
>>> and doesn't need fixing, since that function returns NULL on failure
>>> (after internally cleaning up any partial allocations).
>>>
>>> Fixes: 8290dba51910 ("selftests/bpf: wq: add bpf_wq_start() checks")
>>> Signed-off-by: Kery Qi <qikeyu2017@...il.com>
>> Acked-by: Yonghong Song <yonghong.song@...ux.dev>
>>