[bpf-next,v4,0/8] Typeless/weak ksym for gen_loader + misc fixups

Message

Kumar Kartikeya Dwivedi Oct. 20, 2021, 7:15 p.m. UTC

Patches (1,2,3,6) add typeless and weak ksym support to gen_loader. It is follow
up for the recent kfunc from modules series.

The later patches (7,8) are misc fixes for selftests, and patch 4 for libbpf
where we try to be careful to not end up with fds == 0, as libbpf assumes in
various places that they are greater than 0. Patch 5 fixes up missing O_CLOEXEC
in libbpf.

Please look at patch 4 and 5 closely and whether I missed any other places that
need a change.

Changelog:
----------
v3 -> v4
v3: https://lore.kernel.org/bpf/[e-mail]

 * Remove gpl_only = true from bpf_kallsyms_lookup_name (Alexei)
 * Add bpf_dump_raw_ok check to ensure kptr_restrict isn't bypassed (Alexei)

v2 -> v3
v2: https://lore.kernel.org/bpf/[e-mail]

 * Address feedback from Song
   * Move ksym logging to separate helper to avoid code duplication
   * Move src_reg mask stuff to separate helper
   * Fix various other nits, add acks
     * __builtin_expect is used instead of likely to as skel_internal.h is
       included in isolation.

v1 -> v2
v1: https://lore.kernel.org/bpf/[e-mail]

 * Remove redundant OOM checks in emit_bpf_kallsyms_lookup_name
 * Use designated initializer for sk_lookup fd array (Jakub)
 * Do fd check for all fd returning low level APIs (Andrii, Alexei)
 * Make Fixes: tag quote commit message, use selftests/bpf prefix (Song, Andrii)
 * Split typeless and weak ksym support into separate patches, expand commit
   message (Song)
 * Fix duplication in selftests stemming from use of LSKELS_EXTRA (Song)

Kumar Kartikeya Dwivedi (8):
  bpf: Add bpf_kallsyms_lookup_name helper
  libbpf: Add typeless ksym support to gen_loader
  libbpf: Add weak ksym support to gen_loader
  libbpf: Ensure that BPF syscall fds are never 0, 1, or 2
  libbpf: Use O_CLOEXEC uniformly when opening fds
  selftests/bpf: Add weak/typeless ksym test for light skeleton
  selftests/bpf: Fix fd cleanup in sk_lookup test
  selftests/bpf: Fix memory leak in test_ima

 include/linux/bpf.h                           |   1 +
 include/uapi/linux/bpf.h                      |  16 +++
 kernel/bpf/syscall.c                          |  27 ++++
 tools/include/uapi/linux/bpf.h                |  16 +++
 tools/lib/bpf/bpf.c                           |  28 ++--
 tools/lib/bpf/bpf_gen_internal.h              |  12 +-
 tools/lib/bpf/btf.c                           |   2 +-
 tools/lib/bpf/gen_loader.c                    | 132 ++++++++++++++++--
 tools/lib/bpf/libbpf.c                        |  53 ++++---
 tools/lib/bpf/libbpf_internal.h               |  23 +++
 tools/lib/bpf/libbpf_probes.c                 |   2 +-
 tools/lib/bpf/linker.c                        |   4 +-
 tools/lib/bpf/ringbuf.c                       |   2 +-
 tools/lib/bpf/skel_internal.h                 |  35 ++++-
 tools/lib/bpf/xsk.c                           |   6 +-
 tools/testing/selftests/bpf/Makefile          |   7 +-
 .../selftests/bpf/prog_tests/ksyms_btf.c      |  35 ++++-
 .../selftests/bpf/prog_tests/ksyms_module.c   |  40 +++++-
 .../bpf/prog_tests/ksyms_module_libbpf.c      |  28 ----
 .../selftests/bpf/prog_tests/sk_lookup.c      |  14 +-
 .../selftests/bpf/prog_tests/test_ima.c       |   3 +-
 .../selftests/bpf/progs/test_ksyms_weak.c     |   3 +-
 22 files changed, 374 insertions(+), 115 deletions(-)
 delete mode 100644 tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c