linux-kernel - [RFC PATCH bpf-next 0/4] bpf

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Date:   Mon, 11 Jul 2022 10:32:16 +0200
From:   Artem Savkov <asavkov@...hat.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>, bpf@...r.kernel.org,
        netdev@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Andrea Arcangeli <aarcange@...hat.com>,
        Artem Savkov <asavkov@...hat.com>
Subject: [RFC PATCH bpf-next 0/4] bpf_panic() helper

eBPF is often used for kernel debugging, and one of the widely used and
powerful debugging techniques is post-mortem debugging with a full memory dump.
Triggering a panic at exactly the right moment allows the user to get such a
dump and thus a better view at the system's state. This patchset adds
bpf_panic() helper to do exactly that.

I realize that even though there are multiple guards present, a helper like
this is contrary to BPF being "safe", so this is sent as RFC to have a
discussion on whether adding destructive capabilities is deemed acceptable.

Artem Savkov (4):
  bpf: add a sysctl to enable destructive bpf helpers
  bpf: add BPF_F_DESTRUCTIVE flag for BPF_PROG_LOAD
  bpf: add bpf_panic() helper
  selftests/bpf: bpf_panic selftest

 include/linux/bpf.h                           |   8 +
 include/uapi/linux/bpf.h                      |  13 ++
 kernel/bpf/core.c                             |   1 +
 kernel/bpf/helpers.c                          |  13 ++
 kernel/bpf/syscall.c                          |  33 +++-
 kernel/bpf/verifier.c                         |   7 +
 kernel/trace/bpf_trace.c                      |   2 +
 tools/include/uapi/linux/bpf.h                |  13 ++
 .../selftests/bpf/prog_tests/bpf_panic.c      | 144 ++++++++++++++++++
 9 files changed, 233 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_panic.c

-- 
2.35.3