From: Daniel Borkmann <daniel@iogearbox.net>
To: Eduard Zingerman <eddyz87@gmail.com>,
bpf@vger.kernel.org, ast@kernel.org
Cc: andrii@kernel.org, martin.lau@linux.dev, kernel-team@fb.com,
yonghong.song@linux.dev
Subject: Re: [PATCH bpf-next v1 2/2] selftests/bpf: test with a very short loop
Date: Fri, 18 Oct 2024 13:05:32 +0200 [thread overview]
Message-ID: <50cf504d-865e-481e-9cdf-e6bfa539854e@iogearbox.net> (raw)
In-Reply-To: <20241018020307.1766906-2-eddyz87@gmail.com>
On 10/18/24 4:03 AM, Eduard Zingerman wrote:
> The test added is a simplified reproducer from syzbot report [1].
> If verifier does not insert checkpoint somewhere inside the loop,
> verification of the program would take a very long time.
>
> This would happen because mark_chain_precision() for register r7 would
> constantly trace jump history of the loop back, processing many
> iterations for each mark_chain_precision() call.
>
> [1] https://lore.kernel.org/bpf/670429f6.050a0220.49194.0517.GAE@google.com/
>
> Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
next prev parent reply other threads:[~2024-10-18 11:05 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-18 2:03 [PATCH bpf-next v1 1/2] bpf: force checkpoint when jmp history is too long Eduard Zingerman
2024-10-18 2:03 ` [PATCH bpf-next v1 2/2] selftests/bpf: test with a very short loop Eduard Zingerman
2024-10-18 11:05 ` Daniel Borkmann [this message]
2024-10-18 11:03 ` [PATCH bpf-next v1 1/2] bpf: force checkpoint when jmp history is too long Daniel Borkmann
2024-10-18 16:47 ` Eduard Zingerman
2024-10-21 7:53 ` Daniel Borkmann
2024-10-21 20:23 ` Andrii Nakryiko
2024-10-22 2:03 ` Alexei Starovoitov
2024-10-22 3:19 ` Andrii Nakryiko
2024-10-22 2:18 ` Alexei Starovoitov
2024-10-22 2:27 ` Eduard Zingerman
2024-10-22 2:53 ` Alexei Starovoitov
2024-10-22 5:38 ` Eduard Zingerman
2024-10-23 2:52 ` Eduard Zingerman
2024-10-23 17:31 ` Andrii Nakryiko
-- strict thread matches above, loose matches on Subject: below --
2024-10-09 2:12 [PATCH bpf-next v1 1/2] bpf: force checkpoints at loop back-edges Eduard Zingerman
2024-10-09 2:12 ` [PATCH bpf-next v1 2/2] selftests/bpf: test with a very short loop Eduard Zingerman
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