From: Martin KaFai Lau <martin.lau@linux.dev>
To: Daniel Xu <dxu@dxuuu.xyz>
Cc: pabeni@redhat.com, kuba@kernel.org, andrii@kernel.org,
ast@kernel.org, edumazet@google.com, memxor@gmail.com,
davem@davemloft.net, daniel@iogearbox.net, eddyz87@gmail.com,
song@kernel.org, yonghong.song@linux.dev,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me,
haoluo@google.com, jolsa@kernel.org, horms@kernel.org,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf-next v5 2/5] bpf: tcp: Mark bpf_load_hdr_opt() arg2 as read-write
Date: Mon, 16 Dec 2024 10:18:45 -0800 [thread overview]
Message-ID: <4ed0fa29-dd37-4a7e-8ba6-c84af9d735d6@linux.dev> (raw)
In-Reply-To: <3de5c7e513e3161e040ee0ad6eb8cc4b7d71aa4c.1734045451.git.dxu@dxuuu.xyz>
On 12/12/24 3:22 PM, Daniel Xu wrote:
> MEM_WRITE attribute is defined as: "Non-presence of MEM_WRITE means that
> MEM is only being read". bpf_load_hdr_opt() both reads and writes from
> its arg2 - void *search_res.
>
> This matters a lot for the next commit where we more precisely track
> stack accesses. Without this annotation, the verifier will make false
> assumptions about the contents of memory written to by helpers and
> possibly prune valid branches.
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
next prev parent reply other threads:[~2024-12-16 18:19 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-12 23:22 [PATCH bpf-next v5 0/5] Support eliding map lookup nullness Daniel Xu
2024-12-12 23:22 ` [PATCH bpf-next v5 1/5] bpf: verifier: Add missing newline on verbose() call Daniel Xu
2024-12-12 23:22 ` [PATCH bpf-next v5 2/5] bpf: tcp: Mark bpf_load_hdr_opt() arg2 as read-write Daniel Xu
2024-12-16 18:18 ` Martin KaFai Lau [this message]
2024-12-12 23:22 ` [PATCH bpf-next v5 3/5] bpf: verifier: Refactor helper access type tracking Daniel Xu
2024-12-13 4:04 ` Eduard Zingerman
2024-12-13 20:02 ` Daniel Xu
2024-12-12 23:22 ` [PATCH bpf-next v5 4/5] bpf: verifier: Support eliding map lookup nullness Daniel Xu
2024-12-13 4:04 ` Eduard Zingerman
2024-12-13 20:57 ` Daniel Xu
2024-12-13 23:02 ` Andrii Nakryiko
2024-12-14 2:44 ` Daniel Xu
2024-12-14 3:13 ` Eduard Zingerman
2024-12-16 23:24 ` Andrii Nakryiko
2024-12-19 0:09 ` Daniel Xu
2024-12-19 21:41 ` Daniel Xu
2024-12-20 0:04 ` Eduard Zingerman
2024-12-20 0:40 ` Daniel Xu
2024-12-20 0:43 ` Eduard Zingerman
2024-12-20 0:49 ` Alexei Starovoitov
2024-12-20 4:00 ` Daniel Xu
2024-12-13 23:10 ` Kumar Kartikeya Dwivedi
2024-12-13 23:14 ` Eduard Zingerman
2024-12-13 23:18 ` Eduard Zingerman
2024-12-12 23:22 ` [PATCH bpf-next v5 5/5] bpf: selftests: verifier: Add nullness elision tests Daniel Xu
2024-12-14 6:17 ` Eduard Zingerman
2024-12-18 1:57 ` Daniel Xu
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