On Mon, Jul 11, 2022 at 12:51 PM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > On Mon, Jul 11, 2022 at 10:32:16AM +0200, Artem Savkov wrote: > > 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. > > FWIW I was asked for such helper some time ago from Daniel Vacek, cc-ed Nice :-) This is totally welcome. Though, IIRC, I was asking if I could do a NULL pointer dereference within perf probe (or ftrace) back then. Still, the outcome is similar. So kudos to Artem. --nX > jirka > > > > > 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 > > >
