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

David Vernet
2023-04-04T14:51:40Z

On Mon, Apr 03, 2023 at 09:50:21PM -0700, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@kernel.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@manifault.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/