Re: [PATCH v2 bpf-next 0/3] Fix BPF verifier global subprog context argument logic

Andrii Nakryiko
2023-02-16T19:53:40Z

On Thu, Feb 16, 2023 at 9:40 AM Stanislav Fomichev <sdf@google.com> wrote:
>
> On 02/15, Andrii Nakryiko wrote:
> > Fix kernel bug in determining whether global subprog's argument is
> > PTR_TO_CTX,
> > which is done based on type names. Currently KPROBE programs are broken.
>
> > Add few tests validating that KPROBE context can be passed to global
> > subprog.
> > For that also refactor test_global_funcs test to use test_loader
> > framework.
>
> > v1->v2:
> > - fix compilation warning on arm64 and s390x by force-casting ctx to
> > `void *`, to discard const from `const struct user_pt_regs *`, when
> > passing it to bpf_get_stack().
>
> Such a shame there isn't something like unconstify(typeof(xxx)) :-(
> But thank you for catching this. Need to build a habit of looking at
> the buildbot output.

Yep. And yep, me too :)

>
> Reposting for patchwork:
>
> Acked-by: Stanislav Fomichev <sdf@google.com>

Oh, sorry, forgot to carry over your ack from v1.

>
> > Andrii Nakryiko (3):
> > bpf: fix global subprog context argument resolution logic
> > selftests/bpf: convert test_global_funcs test to test_loader framework
> > selftests/bpf: add global subprog context passing tests
>
> > kernel/bpf/btf.c | 13 +-
> > .../bpf/prog_tests/test_global_funcs.c | 133 +++++-------------
> > .../selftests/bpf/progs/test_global_func1.c | 6 +-
> > .../selftests/bpf/progs/test_global_func10.c | 4 +-
> > .../selftests/bpf/progs/test_global_func11.c | 4 +-
> > .../selftests/bpf/progs/test_global_func12.c | 4 +-
> > .../selftests/bpf/progs/test_global_func13.c | 4 +-
> > .../selftests/bpf/progs/test_global_func14.c | 4 +-
> > .../selftests/bpf/progs/test_global_func15.c | 4 +-
> > .../selftests/bpf/progs/test_global_func16.c | 4 +-
> > .../selftests/bpf/progs/test_global_func17.c | 4 +-
> > .../selftests/bpf/progs/test_global_func2.c | 43 +++++-
> > .../selftests/bpf/progs/test_global_func3.c | 10 +-
> > .../selftests/bpf/progs/test_global_func4.c | 55 +++++++-
> > .../selftests/bpf/progs/test_global_func5.c | 4 +-
> > .../selftests/bpf/progs/test_global_func6.c | 4 +-
> > .../selftests/bpf/progs/test_global_func7.c | 4 +-
> > .../selftests/bpf/progs/test_global_func8.c | 4 +-
> > .../selftests/bpf/progs/test_global_func9.c | 4 +-
> > .../bpf/progs/test_global_func_ctx_args.c | 105 ++++++++++++++
> > 20 files changed, 292 insertions(+), 125 deletions(-)
> > create mode 100644
> > tools/testing/selftests/bpf/progs/test_global_func_ctx_args.c
>
> > --
> > 2.30.2
>