netdev - Re: [PATCH bpf v2 0/4] BPF fixes mixed tail and bpf2bpf calls

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Message-ID: <CAEf4Bzb688kxqzgdrDEc0EgNj7-btzfvJnp6YauTAxSXTkdLow@mail.gmail.com>
Date:   Wed, 16 Jun 2021 21:30:46 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     John Fastabend <john.fastabend@...il.com>
Cc:     Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andriin@...com>,
        Networking <netdev@...r.kernel.org>
Subject: Re: [PATCH bpf v2 0/4] BPF fixes mixed tail and bpf2bpf calls

On Wed, Jun 16, 2021 at 7:34 PM John Fastabend <john.fastabend@...il.com> wrote:
>
> We recently tried to use mixed programs that have both tail calls and
> subprograms, but it needs the attached fixes.
>
> Also added a new test case tailcall_bpf2bpf_5 that simply runs the
> previous test case tailcall_bpf2bpf_4 and adds some "noise". The
> noise here is just a bunch of map calls to get the verifier to insert
> instructions and cause code movement plus it forces used_maps logic
> to be used. Originally, I just extended bpf2bpf_4 directly, but if I
> got the feedback correct it seems the preference is to have another
> test case for this specifically.
>
> With attached patches our programs are happily running with mixed
> subprograms and tailcalls.
>
> Thanks,
> John
>
> ---

Would be nice to include bpf@...r.kernel.org as well. I bet not
everyone interested in BPF follows netdev@...r closely.

>
> John Fastabend (4):
>       bpf: Fix null ptr deref with mixed tail calls and subprogs
>       bpf: map_poke_descriptor is being called with an unstable poke_tab[]
>       bpf: track subprog poke correctly
>       bpf: selftest to verify mixing bpf2bpf calls and tailcalls with insn patch
>
>
>  include/linux/bpf.h                           |  1 +
>  kernel/bpf/core.c                             |  6 ++--
>  kernel/bpf/verifier.c                         | 36 ++++++++++++++-----
>  .../selftests/bpf/prog_tests/tailcalls.c      | 36 +++++++++++++------
>  .../selftests/bpf/progs/tailcall_bpf2bpf4.c   | 20 ++++++++++-
>  5 files changed, 77 insertions(+), 22 deletions(-)
>
> --
>