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  1. Jan 11, 2019
    • Yonghong Song's avatar
      tools/bpf: fix bpftool map dump with bitfields · 298e59d3
      Yonghong Song authored 
      

Commit 8772c8bc ("tools: bpftool: support pretty print
with kind_flag set") added bpftool map dump with kind_flag
support. When bitfield_size can be retrieved directly from
btf_member, function btf_dumper_bitfield() is called to
dump the bitfield. The implementation passed the
wrong parameter "bit_offset" to the function. The excepted
value is the bit_offset within a byte while the passed-in
value is the struct member offset.

This commit fixed the bug with passing correct "bit_offset"
with adjusted data pointer.

Fixes: 8772c8bc ("tools: bpftool: support pretty print with kind_flag set")
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      298e59d3
    • Yonghong Song's avatar
      tools/bpf: test btf bitfield with >=256 struct member offset · e43207fa
      Yonghong Song authored 
      

This patch modified test_btf pretty print test to cover
the bitfield with struct member equal to or greater 256.

Without the previous kernel patch fix, the modified test will fail:

  $ test_btf -p
  ......
  BTF pretty print array(#1)......unexpected pprint output
  expected: 0: {0,0,0,0x3,0x0,0x3,{0|[0,0,0,0,0,0,0,0]},ENUM_ZERO,4,0x1}
      read: 0: {0,0,0,0x3,0x0,0x3,{0|[0,0,0,0,0,0,0,0]},ENUM_ZERO,4,0x0}

  BTF pretty print array(#2)......unexpected pprint output
  expected: 0: {0,0,0,0x3,0x0,0x3,{0|[0,0,0,0,0,0,0,0]},ENUM_ZERO,4,0x1}
      read: 0: {0,0,0,0x3,0x0,0x3,{0|[0,0,0,0,0,0,0,0]},ENUM_ZERO,4,0x0}

  PASS:6 SKIP:0 FAIL:2

With the kernel fix, the modified test will succeed:
  $ test_btf -p
  ......
  BTF pretty print array(#1)......OK
  BTF pretty print array(#2)......OK
  PASS:8 SKIP:0 FAIL:0

Fixes: 9d5f9f70 ("bpf: btf: fix struct/union/fwd types with kind_flag")
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      e43207fa
    • Yonghong Song's avatar
      bpf: fix bpffs bitfield pretty print · 17e3ac81
      Yonghong Song authored 
      

Commit 9d5f9f70 ("bpf: btf: fix struct/union/fwd types
with kind_flag") introduced kind_flag and used bitfield_size
in the btf_member to directly pretty print member values.

The commit contained a bug where the incorrect parameters could be
passed to function btf_bitfield_seq_show(). The bits_offset
parameter in the function expects a value less than 8.
Instead, the member offset in the structure is passed.

The below is btf_bitfield_seq_show() func signature:
  void btf_bitfield_seq_show(void *data, u8 bits_offset,
                             u8 nr_bits, struct seq_file *m)
both bits_offset and nr_bits are u8 type. If the bitfield
member offset is greater than 256, incorrect value will
be printed.

This patch fixed the issue by calculating correct proper
data offset and bits_offset similar to non kind_flag case.

Fixes: 9d5f9f70 ("bpf: btf: fix struct/union/fwd types with kind_flag")
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      17e3ac81
  3. Jan 10, 2019
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