From: Martin KaFai Lau <kafai@fb.com>
To: Hou Tao <houtao@huaweicloud.com>
Cc: bpf@vger.kernel.org, Song Liu <songliubraving@fb.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Hao Sun <sunhao.th@gmail.com>, Hao Luo <haoluo@google.com>,
Andrii Nakryiko <andrii@kernel.org>, Yonghong Song <yhs@fb.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Jiri Olsa <jolsa@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Lorenz Bauer <oss@lmb.io>,
houtao1@huawei.com
Subject: Re: [PATCH bpf-next 3/3] selftests/bpf: Test concurrent updates on bpf_task_storage_busy
Date: Mon, 29 Aug 2022 18:13:50 -0700 [thread overview]
Message-ID: <20220830011350.ig3djlqfume5wqz2@kafai-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20220829142752.330094-4-houtao@huaweicloud.com>
On Mon, Aug 29, 2022 at 10:27:52PM +0800, Hou Tao wrote:
> From: Hou Tao <houtao1@huawei.com>
>
> When there are concurrent task local storage lookup operations,
> if updates on per-cpu bpf_task_storage_busy is not preemption-safe,
> some updates will be lost due to interleave, the final value of
> bpf_task_storage_busy will not be zero and bpf_task_storage_trylock()
> on specific cpu will fail forever.
>
> So add a test case to ensure the update of per-cpu bpf_task_storage_busy
> is preemption-safe.
This test took my setup 1.5 minute to run
and cannot reproduce after running the test in a loop.
Can it be reproduced in a much shorter time ?
If not, test_maps is probably a better place to do the test.
I assume it can be reproduced in arm with this test? Or it can
also be reproduced in other platforms with different kconfig.
Please paste the test failure message and the platform/kconfig
to reproduce it in the commit message.
next prev parent reply other threads:[~2022-08-30 1:14 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-29 14:27 [PATCH bpf-next 0/3] make bpf_task_storage_busy being preemption-safe Hou Tao
2022-08-29 14:27 ` [PATCH bpf-next 1/3] bpf: Use this_cpu_{inc|dec|inc_return} for bpf_task_storage_busy Hou Tao
2022-08-30 0:52 ` Martin KaFai Lau
2022-08-30 2:21 ` Hou Tao
2022-08-31 0:41 ` Martin KaFai Lau
2022-08-31 2:04 ` Hou Tao
2022-08-29 14:27 ` [PATCH bpf-next 2/3] selftests/bpf: Move sys_pidfd_open() into test_progs.h Hou Tao
2022-08-29 14:27 ` [PATCH bpf-next 3/3] selftests/bpf: Test concurrent updates on bpf_task_storage_busy Hou Tao
2022-08-30 1:13 ` Martin KaFai Lau [this message]
2022-08-30 2:37 ` Hou Tao
2022-08-31 0:47 ` Martin KaFai Lau
2022-08-31 2:07 ` Hou Tao
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