From: Quanyang Wang <quanyang.wang@windriver.com>
To: "Ming Lei" <ming.lei@redhat.com>, "Michal Koutný" <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, Jens Axboe <axboe@kernel.dk>,
Roman Gushchin <guro@fb.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [V2][PATCH] cgroup: fix memory leak caused by missing cgroup_bpf_offline
Date: Wed, 20 Oct 2021 13:22:06 +0800 [thread overview]
Message-ID: <7a21a20d-eb12-e491-4e69-4e043b3b6d8d@windriver.com> (raw)
In-Reply-To: <YW98RTBdzqin+9Ko@T590>
Hi Ming,
On 10/20/21 10:17 AM, Ming Lei wrote:
> On Tue, Oct 19, 2021 at 07:10:26PM +0200, Michal Koutný wrote:
>> Hi.
>>
>> On Tue, Oct 19, 2021 at 06:41:14PM +0800, Quanyang Wang <quanyang.wang@windriver.com> wrote:
>>> So I add 2 "Fixes tags" here to indicate that 2 commits introduce two
>>> different issues.
>>
>> AFAIU, both the changes are needed to cause the leak, a single patch
>> alone won't cause the issue. Is that correct? (Perhaps not as I realize,
>> see below.)
>>
>> But on second thought, the problem is the missing percpu_ref_exit() in
>> the (root) cgroup release path and percpu counter would allocate the
>> percpu_count_ptr anyway, so 4bfc0bb2c60e is only making the leak more
>> visible. Is this correct?
>>
>> I agree the commit 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of
>> percpu_ref in fast path") alone did nothing wrong.
>
> If only precpu_ref data is leaked, it is fine to add "Fixes: 2b0d3d3e4fcf",
> I thought cgroup_bpf_release() needs to release more for root cgroup, but
> looks not true.
For now, I can only observe that precpu_ref data is leaked when running
ltp testsuite.
Thanks,
Quanyang
>
>
> Thanks,
> Ming
>
WARNING: multiple messages have this Message-ID (diff)
From: Quanyang Wang <quanyang.wang@windriver.com>
To: "Ming Lei" <ming.lei@redhat.com>, "Michal Koutný" <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, Jens Axboe <axboe@kernel.dk>,
Roman Gushchin <guro@fb.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [V2][PATCH] cgroup: fix memory leak caused by missing cgroup_bpf_offline
Date: Wed, 20 Oct 2021 13:22:06 +0800 [thread overview]
Message-ID: <7a21a20d-eb12-e491-4e69-4e043b3b6d8d@windriver.com> (raw)
In-Reply-To: <YW98RTBdzqin+9Ko@T590>
Hi Ming,
On 10/20/21 10:17 AM, Ming Lei wrote:
> On Tue, Oct 19, 2021 at 07:10:26PM +0200, Michal Koutný wrote:
>> Hi.
>>
>> On Tue, Oct 19, 2021 at 06:41:14PM +0800, Quanyang Wang <quanyang.wang@windriver.com> wrote:
>>> So I add 2 "Fixes tags" here to indicate that 2 commits introduce two
>>> different issues.
>>
>> AFAIU, both the changes are needed to cause the leak, a single patch
>> alone won't cause the issue. Is that correct? (Perhaps not as I realize,
>> see below.)
>>
>> But on second thought, the problem is the missing percpu_ref_exit() in
>> the (root) cgroup release path and percpu counter would allocate the
>> percpu_count_ptr anyway, so 4bfc0bb2c60e is only making the leak more
>> visible. Is this correct?
>>
>> I agree the commit 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of
>> percpu_ref in fast path") alone did nothing wrong.
>
> If only precpu_ref data is leaked, it is fine to add "Fixes: 2b0d3d3e4fcf",
> I thought cgroup_bpf_release() needs to release more for root cgroup, but
> looks not true.
For now, I can only observe that precpu_ref data is leaked when running
ltp testsuite.
Thanks,
Quanyang
>
>
> Thanks,
> Ming
>
next prev parent reply other threads:[~2021-10-20 5:22 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 7:56 [V2][PATCH] cgroup: fix memory leak caused by missing cgroup_bpf_offline quanyang.wang
2021-10-18 9:02 ` Ming Lei
2021-10-18 10:06 ` Quanyang Wang
2021-10-18 12:59 ` Ming Lei
2021-10-18 12:59 ` Ming Lei
2021-10-19 10:41 ` Quanyang Wang
2021-10-19 10:41 ` Quanyang Wang
2021-10-19 17:10 ` Michal Koutný
2021-10-20 2:17 ` Ming Lei
2021-10-20 5:22 ` Quanyang Wang [this message]
2021-10-20 5:22 ` Quanyang Wang
2021-10-20 17:28 ` Michal Koutný
2021-10-22 11:03 ` Quanyang Wang
2021-10-22 11:03 ` Quanyang Wang
2021-10-20 5:16 ` Quanyang Wang
2021-10-20 5:16 ` Quanyang Wang
2021-10-19 10:41 ` Quanyang Wang
2021-10-22 1:30 ` Roman Gushchin
2021-10-22 1:30 ` Roman Gushchin
2021-10-22 11:55 ` Quanyang Wang
2021-10-22 21:29 ` Alexei Starovoitov
2021-10-22 21:29 ` Alexei Starovoitov
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