netdev - Re: [PATCH bpf-next 0/8] bpf: Follow up to RCU enforcement in the verifier.

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Message-ID: <20230404145131.GB3896@maniforge>
Date:   Tue, 4 Apr 2023 09:51:31 -0500
From:   David Vernet <void@...ifault.com>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     davem@...emloft.net, daniel@...earbox.net, andrii@...nel.org,
        martin.lau@...nel.org, davemarchevsky@...a.com, tj@...nel.org,
        memxor@...il.com, netdev@...r.kernel.org, bpf@...r.kernel.org,
        kernel-team@...com
Subject: Re: [PATCH bpf-next 0/8] bpf: Follow up to RCU enforcement in the
 verifier.

On Mon, Apr 03, 2023 at 09:50:21PM -0700, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@...nel.org>
> 
> The patch set is addressing a fallout from
> commit 6fcd486b3a0a ("bpf: Refactor RCU enforcement in the verifier.")
> It was too aggressive with PTR_UNTRUSTED marks.
> Patches 1-6 are cleanup and adding verifier smartness to address real
> use cases in bpf programs that broke with too aggressive PTR_UNTRUSTED.
> The partial revert is done in patch 7 anyway.
> 
> Alexei Starovoitov (8):
>   bpf: Invoke btf_struct_access() callback only for writes.
>   bpf: Remove unused arguments from btf_struct_access().
>   bpf: Refactor btf_nested_type_is_trusted().
>   bpf: Teach verifier that certain helpers accept NULL pointer.
>   bpf: Refactor NULL-ness check in check_reg_type().
>   bpf: Allowlist few fields similar to __rcu tag.
>   bpf: Undo strict enforcement for walking untagged fields.
>   selftests/bpf: Add tracing tests for walking skb and req.

For whole series:

Acked-by: David Vernet <void@...ifault.com>

I left one comment on 4/8 in [0], but it's not a blocker and everything
else LGTM.

[0]: https://lore.kernel.org/all/20230404144652.GA3896@maniforge/