From: Eduard Zingerman <eddyz87@gmail.com>
To: Daniel Xu <dxu@dxuuu.xyz>,
daniel@iogearbox.net, andrii@kernel.org, ast@kernel.org
Cc: john.fastabend@gmail.com, martin.lau@linux.dev, song@kernel.org,
yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me,
haoluo@google.com, jolsa@kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, mhartmay@linux.ibm.com,
iii@linux.ibm.com
Subject: Re: [PATCH bpf-next 3/3] bpf: verifier: Disambiguate get_constant_map_key() errors
Date: Mon, 03 Feb 2025 10:49:32 -0800 [thread overview]
Message-ID: <3f392f10e29f651836bf28e342150a6169e6e0d9.camel@gmail.com> (raw)
In-Reply-To: <91d84512b4082e5eb095b31e5536944a3d53f0eb.1738439839.git.dxu@dxuuu.xyz>
On Sat, 2025-02-01 at 12:58 -0700, Daniel Xu wrote:
> Refactor get_constant_map_key() to disambiguate the constant key
> value from potential error values. In the case that the key is
> negative, it could be confused for an error.
>
> It's not currently an issue, as the verifier seems to track s32 spills
> as u32. So even if the program wrongly uses a negative value for an
> arraymap key, the verifier just thinks it's an impossibly high value
> which gets correctly discarded.
>
> Refactor anyways to make things cleaner and prevent potential future
> issues.
>
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> ---
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
[...]
prev parent reply other threads:[~2025-02-03 18:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-01 19:58 [PATCH bpf-next 0/3] bpf: Some fixes for nullness elision Daniel Xu
2025-02-01 19:58 ` [PATCH bpf-next 1/3] bpf: verifier: Do not extract constant map keys for irrelevant maps Daniel Xu
2025-02-03 18:45 ` Eduard Zingerman
2025-02-04 9:09 ` Daniel Xu
2025-02-01 19:58 ` [PATCH bpf-next 2/3] bpf: selftests: Test constant key extraction on " Daniel Xu
2025-02-03 18:48 ` Eduard Zingerman
2025-02-01 19:58 ` [PATCH bpf-next 3/3] bpf: verifier: Disambiguate get_constant_map_key() errors Daniel Xu
2025-02-03 18:49 ` Eduard Zingerman [this message]
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