From:   Alexander Lobakin <aleksander.lobakin@intel.com>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>
Cc:     Alexander Lobakin <aleksander.lobakin@intel.com>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Larysa Zaremba <larysa.zaremba@intel.com>,
        =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>,
        Ilya Leoshkevich <iii@linux.ibm.com>,
        Song Liu <song@kernel.org>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        Jakub Kicinski <kuba@kernel.org>, bpf@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH bpf-next 0/2] double-fix bpf_test_run + XDP_PASS recycling
Date:   Thu, 16 Mar 2023 18:50:49 +0100
Message-Id: <20230316175051.922550-1-aleksander.lobakin@intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Enabling skb PP recycling revealed a couple issues in the bpf_test_run
code. Recycling broke the assumption that the headroom won't ever be
touched during the test_run execution: xdp_scrub_frame() invalidates the
XDP frame at the headroom start, while neigh xmit code overwrites 2 bytes
to the left of the Ethernet header. The first makes the kernel panic in
certain cases, while the second breaks xdp_do_redirect selftest on BE.
test_run is a limited-scope entity, so let's hope no more corner cases
will happen here or at least they will be as easy and pleasant to fix
as those two.

Alexander Lobakin (2):
  bpf, test_run: fix crashes due to XDP frame overwriting/corruption
  selftests/bpf: fix "metadata marker" getting overwritten by the
    netstack

 net/bpf/test_run.c                                   | 12 +++++++++++-
 .../selftests/bpf/prog_tests/xdp_do_redirect.c       |  7 ++++---
 .../selftests/bpf/progs/test_xdp_do_redirect.c       |  2 +-
 3 files changed, 16 insertions(+), 5 deletions(-)

-- 
2.39.2