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* [PATCH bpf 0/4] Fix caching of BTF for kfuncs in the verifier
@ 2024-10-08 10:35 Toke Høiland-Jørgensen
  2024-10-08 10:35 ` [PATCH bpf 1/4] bpf: fix kfunc btf caching for modules Toke Høiland-Jørgensen
                   ` (3 more replies)
  0 siblings, 4 replies; 20+ messages in thread
From: Toke Høiland-Jørgensen @ 2024-10-08 10:35 UTC (permalink / raw)
  To: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
	Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
	Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
	Kumar Kartikeya Dwivedi
  Cc: Simon Sundberg, bpf, netdev, Toke Høiland-Jørgensen

When playing around with defining kfuncs in some custom modules, we
noticed that if a BPF program calls two functions with the same
signature in two different modules, the function from the wrong module
may sometimes end up being called. Whether this happens depends on the
order of the calls in the BPF program, which turns out to be due to the
use of sort() inside __find_kfunc_desc_btf() in the verifier code.

This series contains a fix for the issue (first patch), and a selftest
to trigger it (last patch). The two middle commits refactor some of the
selftest code to better handle building and loading multiple kernel
modules as part of the testing. See the individual patch descriptions
for more details.

---
Simon Sundberg (2):
      selftests/bpf: Provide a generic [un]load_module helper
      selftests/bpf: Add test for kfunc module order

Toke Høiland-Jørgensen (2):
      bpf: fix kfunc btf caching for modules
      selftests/bpf: Consolidate kernel modules into common directory

 kernel/bpf/verifier.c                              |  8 +++-
 tools/testing/selftests/bpf/Makefile               | 35 +++++++-------
 .../testing/selftests/bpf/bpf_test_no_cfi/Makefile | 19 --------
 tools/testing/selftests/bpf/bpf_testmod/Makefile   | 20 --------
 .../testing/selftests/bpf/prog_tests/core_reloc.c  |  2 +-
 .../selftests/bpf/prog_tests/kfunc_module_order.c  | 55 ++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/bad_struct_ops.c |  2 +-
 tools/testing/selftests/bpf/progs/cb_refs.c        |  2 +-
 tools/testing/selftests/bpf/progs/epilogue_exit.c  |  4 +-
 .../selftests/bpf/progs/epilogue_tailcall.c        |  4 +-
 tools/testing/selftests/bpf/progs/iters_testmod.c  |  2 +-
 tools/testing/selftests/bpf/progs/jit_probe_mem.c  |  2 +-
 .../selftests/bpf/progs/kfunc_call_destructive.c   |  2 +-
 .../testing/selftests/bpf/progs/kfunc_call_fail.c  |  2 +-
 .../testing/selftests/bpf/progs/kfunc_call_race.c  |  2 +-
 .../testing/selftests/bpf/progs/kfunc_call_test.c  |  2 +-
 .../selftests/bpf/progs/kfunc_call_test_subprog.c  |  2 +-
 .../selftests/bpf/progs/kfunc_module_order.c       | 30 ++++++++++++
 .../testing/selftests/bpf/progs/local_kptr_stash.c |  2 +-
 tools/testing/selftests/bpf/progs/map_kptr.c       |  2 +-
 tools/testing/selftests/bpf/progs/map_kptr_fail.c  |  2 +-
 tools/testing/selftests/bpf/progs/missed_kprobe.c  |  2 +-
 .../selftests/bpf/progs/missed_kprobe_recursion.c  |  2 +-
 tools/testing/selftests/bpf/progs/nested_acquire.c |  2 +-
 tools/testing/selftests/bpf/progs/pro_epilogue.c   |  4 +-
 .../selftests/bpf/progs/pro_epilogue_goto_start.c  |  4 +-
 tools/testing/selftests/bpf/progs/sock_addr_kern.c |  2 +-
 .../selftests/bpf/progs/struct_ops_detach.c        |  2 +-
 .../selftests/bpf/progs/struct_ops_forgotten_cb.c  |  2 +-
 .../selftests/bpf/progs/struct_ops_maybe_null.c    |  2 +-
 .../bpf/progs/struct_ops_maybe_null_fail.c         |  2 +-
 .../selftests/bpf/progs/struct_ops_module.c        |  2 +-
 .../selftests/bpf/progs/struct_ops_multi_pages.c   |  2 +-
 .../selftests/bpf/progs/struct_ops_nulled_out_cb.c |  2 +-
 .../bpf/progs/test_kfunc_param_nullable.c          |  2 +-
 .../selftests/bpf/progs/test_module_attach.c       |  2 +-
 .../selftests/bpf/progs/test_tp_btf_nullable.c     |  2 +-
 .../testing/selftests/bpf/progs/unsupported_ops.c  |  2 +-
 tools/testing/selftests/bpf/progs/wq.c             |  2 +-
 tools/testing/selftests/bpf/progs/wq_failures.c    |  2 +-
 .../bpf/{bpf_testmod => test_kmods}/.gitignore     |  0
 tools/testing/selftests/bpf/test_kmods/Makefile    | 26 ++++++++++
 .../selftests/bpf/test_kmods/bpf_test_modorder_x.c | 39 +++++++++++++++
 .../selftests/bpf/test_kmods/bpf_test_modorder_y.c | 39 +++++++++++++++
 .../bpf_test_no_cfi.c                              |  0
 .../bpf_testmod-events.h                           |  0
 .../bpf/{bpf_testmod => test_kmods}/bpf_testmod.c  |  0
 .../bpf/{bpf_testmod => test_kmods}/bpf_testmod.h  |  0
 .../bpf_testmod_kfunc.h                            |  0
 tools/testing/selftests/bpf/testing_helpers.c      | 34 ++++++++-----
 tools/testing/selftests/bpf/testing_helpers.h      |  2 +
 51 files changed, 275 insertions(+), 108 deletions(-)
---
base-commit: bcd28cfd04ebd3f871443e4746e511147686e517
change-id: 20241008-fix-kfunc-btf-caching-for-modules-b62603484ffb

Best regards,
-- 
Toke Høiland-Jørgensen <toke@redhat.com>


^ permalink raw reply	[flat|nested] 20+ messages in thread

end of thread, other threads:[~2024-10-10  8:59 UTC | newest]

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2024-10-08 10:35 [PATCH bpf 0/4] Fix caching of BTF for kfuncs in the verifier Toke Høiland-Jørgensen
2024-10-08 10:35 ` [PATCH bpf 1/4] bpf: fix kfunc btf caching for modules Toke Høiland-Jørgensen
2024-10-08 17:46   ` Jiri Olsa
2024-10-09  1:43   ` Kumar Kartikeya Dwivedi
2024-10-08 10:35 ` [PATCH bpf 2/4] selftests/bpf: Consolidate kernel modules into common directory Toke Høiland-Jørgensen
2024-10-08 17:46   ` Jiri Olsa
2024-10-08 17:55     ` Toke Høiland-Jørgensen
2024-10-08 18:18       ` Jiri Olsa
2024-10-08 18:23         ` Toke Høiland-Jørgensen
2024-10-09  2:08   ` Alexei Starovoitov
2024-10-09  7:39     ` Toke Høiland-Jørgensen
2024-10-09 23:36       ` Alexei Starovoitov
2024-10-10  8:59         ` Toke Høiland-Jørgensen
2024-10-08 10:35 ` [PATCH bpf 3/4] selftests/bpf: Provide a generic [un]load_module helper Toke Høiland-Jørgensen
2024-10-08 17:54   ` Jiri Olsa
2024-10-09  1:44   ` Kumar Kartikeya Dwivedi
2024-10-08 10:35 ` [PATCH bpf 4/4] selftests/bpf: Add test for kfunc module order Toke Høiland-Jørgensen
2024-10-08 17:46   ` Jiri Olsa
2024-10-08 18:05     ` Toke Høiland-Jørgensen
2024-10-09  2:09   ` Kumar Kartikeya Dwivedi

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