From 298e59d322954e89ed2a556c601a04a4c007d1b3 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 10 Jan 2019 11:14:02 -0800 Subject: [PATCH] tools/bpf: fix bpftool map dump with bitfields Commit 8772c8bc093b ("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: 8772c8bc093b ("tools: bpftool: support pretty print with kind_flag set") Acked-by: Martin KaFai Lau Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann --- tools/bpf/bpftool/btf_dumper.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c index 3f0629edbca5..6ba5f567a9d8 100644 --- a/tools/bpf/bpftool/btf_dumper.c +++ b/tools/bpf/bpftool/btf_dumper.c @@ -82,8 +82,6 @@ static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset, int bits_to_copy; __u64 print_num; - data += BITS_ROUNDDOWN_BYTES(bit_offset); - bit_offset = BITS_PER_BYTE_MASKED(bit_offset); bits_to_copy = bit_offset + nr_bits; bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy); @@ -118,7 +116,9 @@ static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset, * BTF_INT_OFFSET() cannot exceed 64 bits. */ total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type); - btf_dumper_bitfield(nr_bits, total_bits_offset, data, jw, + data += BITS_ROUNDDOWN_BYTES(total_bits_offset); + bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset); + btf_dumper_bitfield(nr_bits, bit_offset, data, jw, is_plain_text); } @@ -216,11 +216,12 @@ static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id, } jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off)); + data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset); if (bitfield_size) { - btf_dumper_bitfield(bitfield_size, bit_offset, - data, d->jw, d->is_plain_text); + btf_dumper_bitfield(bitfield_size, + BITS_PER_BYTE_MASKED(bit_offset), + data_off, d->jw, d->is_plain_text); } else { - data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset); ret = btf_dumper_do_type(d, m[i].type, BITS_PER_BYTE_MASKED(bit_offset), data_off);