From: Eduard Zingerman <eddyz87@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org,
daniel@iogearbox.net, martin.lau@linux.dev, kernel-team@fb.com,
yonghong.song@linux.dev, memxor@gmail.com, awerner32@gmail.com
Subject: Re: [PATCH bpf 11/12] selftests/bpf: add __not_msg annotation for test_loader based tests
Date: Fri, 17 Nov 2023 20:53:26 +0200 [thread overview]
Message-ID: <d6e728aa421b08544b982a0ce60148ef45af7b53.camel@gmail.com> (raw)
In-Reply-To: <CAEf4BzZhEU-h0yfY2WCBfPDjmwOzxxw1a70J4c78Bix34W70QQ@mail.gmail.com>
On Fri, 2023-11-17 at 11:45 -0500, Andrii Nakryiko wrote:
[...]
> I think this implementation has an undesired surprising behavior.
> Imagine you have a log like this:
>
> A
> C
> D
> B
>
>
> And you specify
>
> __msg("A")
> __nomsg("B")
> __msg("C")
> __msg("D")
> __msg("B")
>
> Log matches the spec, right? But your implementation will eagerly reject it.
>
> I think you can implement more coherent behavior if you only strstr()
> __msg() specs, skipping __nomsg() first. But on each __msg one, if
> successful, you go back and validate that there are no matches for all
> __nomsg() specs that you skipped, taking into account matched
> positions for current __msg() and last __msg() (or the start of the
> log, of course).
>
> Not sure if I explained clearly, but the idea is to postpone __nomsg()
> until we anchor ourselves between two __msg()s. And beginning/end of
> verifier log are two other anchoring positions.
Yes, makes total sense, thank you for spotting it. I can fix this and
submit this patch as an unrelated change or just drop it, what would
you prefer?
next prev parent reply other threads:[~2023-11-17 18:53 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-16 2:17 [PATCH bpf 00/12] verify callbacks as if they are called unknown number of times Eduard Zingerman
2023-11-16 2:17 ` [PATCH bpf 01/12] selftests/bpf: track tcp payload offset as scalar in xdp_synproxy Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-16 2:17 ` [PATCH bpf 02/12] selftests/bpf: track string payload offset as scalar in strobemeta Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-17 18:52 ` Eduard Zingerman
2023-11-16 2:17 ` [PATCH bpf 03/12] selftests/bpf: fix bpf_loop_bench for new callback verification scheme Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-17 18:52 ` Eduard Zingerman
2023-11-17 21:38 ` Alexei Starovoitov
2023-11-17 21:43 ` Eduard Zingerman
2023-11-17 21:47 ` Alexei Starovoitov
2023-11-17 21:50 ` Eduard Zingerman
2023-11-17 21:55 ` Alexei Starovoitov
2023-11-16 2:17 ` [PATCH bpf 04/12] bpf: extract __check_reg_arg() utility function Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-16 2:17 ` [PATCH bpf 05/12] bpf: extract setup_func_entry() " Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-17 18:52 ` Eduard Zingerman
2023-11-16 2:17 ` [PATCH bpf 06/12] bpf: verify callbacks as if they are called unknown number of times Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-17 18:52 ` Eduard Zingerman
2023-11-17 20:27 ` Andrii Nakryiko
2023-11-17 21:03 ` Eduard Zingerman
2023-11-16 2:17 ` [PATCH bpf 07/12] selftests/bpf: tests for iterating callbacks Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-16 2:17 ` [PATCH bpf 08/12] bpf: widening for callback iterators Eduard Zingerman
2023-11-17 16:46 ` Andrii Nakryiko
2023-11-16 2:18 ` [PATCH bpf 09/12] selftests/bpf: test widening for iterating callbacks Eduard Zingerman
2023-11-17 16:47 ` Andrii Nakryiko
2023-11-17 18:53 ` Eduard Zingerman
2023-11-17 20:28 ` Andrii Nakryiko
2023-11-16 2:18 ` [PATCH bpf 10/12] bpf: keep track of max number of bpf_loop callback iterations Eduard Zingerman
2023-11-16 14:08 ` Andrii Nakryiko
2023-11-16 14:13 ` Eduard Zingerman
2023-11-17 16:47 ` Andrii Nakryiko
2023-11-17 18:53 ` Eduard Zingerman
2023-11-17 20:30 ` Andrii Nakryiko
2023-11-16 2:18 ` [PATCH bpf 11/12] selftests/bpf: add __not_msg annotation for test_loader based tests Eduard Zingerman
2023-11-17 16:45 ` Andrii Nakryiko
2023-11-17 18:53 ` Eduard Zingerman [this message]
2023-11-17 20:31 ` Andrii Nakryiko
2023-11-17 21:10 ` Eduard Zingerman
2023-11-17 21:33 ` Alexei Starovoitov
2023-11-16 2:18 ` [PATCH bpf 12/12] selftests/bpf: check if max number of bpf_loop iterations is tracked Eduard Zingerman
2023-11-17 16:47 ` Andrii Nakryiko
2023-11-17 18:53 ` Eduard Zingerman
2023-11-17 20:32 ` Andrii Nakryiko
2023-11-17 21:18 ` Eduard Zingerman
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