From: Eduard Zingerman <eddyz87@gmail.com>
To: Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org
Cc: kernel-team@meta.com
Subject: Re: [PATCH bpf-next 05/10] selftests/bpf: add selftest validating callback result is enforced
Date: Wed, 22 Nov 2023 17:13:12 +0200 [thread overview]
Message-ID: <4b12e29372014a46a399ee26870c306fa492319d.camel@gmail.com> (raw)
In-Reply-To: <20231122011656.1105943-6-andrii@kernel.org>
On Tue, 2023-11-21 at 17:16 -0800, Andrii Nakryiko wrote:
> BPF verifier expects callback subprogs to return values from specified
> range (typically [0, 1]). This requires that r0 at exit is both precise
> (because we rely on specific value range) and is marked as read
> (otherwise state comparison will ignore such register as unimportant).
>
> Add a simple test that validates that all these conditions are enforced.
>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
[...]
> +SEC("?raw_tp")
> +__failure __log_level(2)
> +__flag(BPF_F_TEST_STATE_FREQ)
Nit: although it is redundant, but maybe also check precision log to
check that r0 is indeed marked precise?
> +__msg("from 10 to 12: frame1: R0=scalar(umin=1001) R10=fp0 cb")
> +__msg("At callback return the register R0 has unknown scalar value should have been in (0x0; 0x1)")
> +__naked int callback_precise_return_fail(void)
[...]
next prev parent reply other threads:[~2023-11-22 15:13 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-22 1:16 [PATCH bpf-next 00/10] BPF verifier retval logic fixes Andrii Nakryiko
2023-11-22 1:16 ` [PATCH bpf-next 01/10] bpf: rearrange bpf_func_state fields to save a bit of memory Andrii Nakryiko
2023-11-22 15:12 ` Eduard Zingerman
2023-11-22 1:16 ` [PATCH bpf-next 02/10] bpf: provide correct register name for exception callback retval check Andrii Nakryiko
2023-11-22 15:12 ` Eduard Zingerman
2023-11-23 1:44 ` Alexei Starovoitov
2023-11-24 3:39 ` Andrii Nakryiko
2023-11-22 1:16 ` [PATCH bpf-next 03/10] bpf: enforce precision of R0 on callback return Andrii Nakryiko
2023-11-22 15:12 ` Eduard Zingerman
2023-11-22 1:16 ` [PATCH bpf-next 04/10] bpf: enforce exact retval range on subprog/callback exit Andrii Nakryiko
2023-11-22 15:13 ` Eduard Zingerman
2023-11-22 17:45 ` Andrii Nakryiko
2023-11-27 10:55 ` Shung-Hsi Yu
2023-11-27 18:19 ` Andrii Nakryiko
2023-11-22 1:16 ` [PATCH bpf-next 05/10] selftests/bpf: add selftest validating callback result is enforced Andrii Nakryiko
2023-11-22 15:13 ` Eduard Zingerman [this message]
2023-11-22 17:46 ` Andrii Nakryiko
2023-11-22 1:16 ` [PATCH bpf-next 06/10] bpf: enforce precise retval range on program exit Andrii Nakryiko
2023-11-22 15:13 ` Eduard Zingerman
2023-11-22 1:16 ` [PATCH bpf-next 07/10] bpf: unify async callback and program retval checks Andrii Nakryiko
2023-11-22 15:13 ` Eduard Zingerman
2023-11-22 1:16 ` [PATCH bpf-next 08/10] bpf: enforce precision of R0 on program/async callback return Andrii Nakryiko
2023-11-22 15:13 ` Eduard Zingerman
2023-11-22 1:16 ` [PATCH bpf-next 09/10] selftests/bpf: validate async callback return value check correctness Andrii Nakryiko
2023-11-22 15:13 ` Eduard Zingerman
2023-11-22 1:16 ` [PATCH bpf-next 10/10] selftests/bpf: adjust global_func15 test to validate prog exit precision Andrii Nakryiko
2023-11-22 15:13 ` Eduard Zingerman
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