[RFC PATCH bpf-next 0/4] bpf_panic() helper

From: Artem Savkov
Date: Mon Jul 11 2022 - 04:33:15 EST


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