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borkmannborkmann
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Merge branch 'bpf-fix-bitfield-printing'
Yonghong Song says: ==================== The previous BTF kind_flag support patch set introduced a bug for kernel bpffs pretty printing and another bug for bpftool map pretty printing. If a bitfield struct member offset is greater than 256 bits, printed value for that struct member will be incorrect. - Patch #1 fixed the bug in kernel bpffs pretty printing. - Patch #2 enhanced the test_btf test case to cover the issue exposed by patch #1. - Patch #3 fixed the bug in bpftool map pretty printing. ==================== Signed-off-by: Daniel Borkmann <[email protected]>
2 parents beaf3d1 + 298e59d commit fb4129b

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3 files changed

+34
-20
lines changed

3 files changed

+34
-20
lines changed

‎kernel/bpf/btf.c

+6-6
Original file line numberDiff line numberDiff line change
@@ -1219,8 +1219,6 @@ static void btf_bitfield_seq_show(void *data, u8 bits_offset,
12191219
u8 nr_copy_bits;
12201220
u64 print_num;
12211221

1222-
data += BITS_ROUNDDOWN_BYTES(bits_offset);
1223-
bits_offset = BITS_PER_BYTE_MASKED(bits_offset);
12241222
nr_copy_bits = nr_bits + bits_offset;
12251223
nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
12261224

@@ -1255,7 +1253,9 @@ static void btf_int_bits_seq_show(const struct btf *btf,
12551253
* BTF_INT_OFFSET() cannot exceed 64 bits.
12561254
*/
12571255
total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
1258-
btf_bitfield_seq_show(data, total_bits_offset, nr_bits, m);
1256+
data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
1257+
bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
1258+
btf_bitfield_seq_show(data, bits_offset, nr_bits, m);
12591259
}
12601260

12611261
static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
@@ -2001,12 +2001,12 @@ static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
20012001

20022002
member_offset = btf_member_bit_offset(t, member);
20032003
bitfield_size = btf_member_bitfield_size(t, member);
2004+
bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
2005+
bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
20042006
if (bitfield_size) {
2005-
btf_bitfield_seq_show(data, member_offset,
2007+
btf_bitfield_seq_show(data + bytes_offset, bits8_offset,
20062008
bitfield_size, m);
20072009
} else {
2008-
bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
2009-
bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
20102010
ops = btf_type_ops(member_type);
20112011
ops->seq_show(btf, member_type, member->type,
20122012
data + bytes_offset, bits8_offset, m);

‎tools/bpf/bpftool/btf_dumper.c

+7-6
Original file line numberDiff line numberDiff line change
@@ -82,8 +82,6 @@ static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
8282
int bits_to_copy;
8383
__u64 print_num;
8484

85-
data += BITS_ROUNDDOWN_BYTES(bit_offset);
86-
bit_offset = BITS_PER_BYTE_MASKED(bit_offset);
8785
bits_to_copy = bit_offset + nr_bits;
8886
bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
8987

@@ -118,7 +116,9 @@ static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
118116
* BTF_INT_OFFSET() cannot exceed 64 bits.
119117
*/
120118
total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
121-
btf_dumper_bitfield(nr_bits, total_bits_offset, data, jw,
119+
data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
120+
bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
121+
btf_dumper_bitfield(nr_bits, bit_offset, data, jw,
122122
is_plain_text);
123123
}
124124

@@ -216,11 +216,12 @@ static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
216216
}
217217

218218
jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
219+
data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
219220
if (bitfield_size) {
220-
btf_dumper_bitfield(bitfield_size, bit_offset,
221-
data, d->jw, d->is_plain_text);
221+
btf_dumper_bitfield(bitfield_size,
222+
BITS_PER_BYTE_MASKED(bit_offset),
223+
data_off, d->jw, d->is_plain_text);
222224
} else {
223-
data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
224225
ret = btf_dumper_do_type(d, m[i].type,
225226
BITS_PER_BYTE_MASKED(bit_offset),
226227
data_off);

‎tools/testing/selftests/bpf/test_btf.c

+21-8
Original file line numberDiff line numberDiff line change
@@ -3526,6 +3526,8 @@ struct pprint_mapv {
35263526
ENUM_TWO,
35273527
ENUM_THREE,
35283528
} aenum;
3529+
uint32_t ui32b;
3530+
uint32_t bits2c:2;
35293531
};
35303532

35313533
static struct btf_raw_test pprint_test_template[] = {
@@ -3568,7 +3570,7 @@ static struct btf_raw_test pprint_test_template[] = {
35683570
BTF_ENUM_ENC(NAME_TBD, 2),
35693571
BTF_ENUM_ENC(NAME_TBD, 3),
35703572
/* struct pprint_mapv */ /* [16] */
3571-
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 8), 32),
3573+
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 10), 40),
35723574
BTF_MEMBER_ENC(NAME_TBD, 11, 0), /* uint32_t ui32 */
35733575
BTF_MEMBER_ENC(NAME_TBD, 10, 32), /* uint16_t ui16 */
35743576
BTF_MEMBER_ENC(NAME_TBD, 12, 64), /* int32_t si32 */
@@ -3577,9 +3579,11 @@ static struct btf_raw_test pprint_test_template[] = {
35773579
BTF_MEMBER_ENC(NAME_TBD, 6, 126), /* unused_bits2b */
35783580
BTF_MEMBER_ENC(0, 14, 128), /* union (anon) */
35793581
BTF_MEMBER_ENC(NAME_TBD, 15, 192), /* aenum */
3582+
BTF_MEMBER_ENC(NAME_TBD, 11, 224), /* uint32_t ui32b */
3583+
BTF_MEMBER_ENC(NAME_TBD, 6, 256), /* bits2c */
35803584
BTF_END_RAW,
35813585
},
3582-
BTF_STR_SEC("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum"),
3586+
BTF_STR_SEC("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum\0ui32b\0bits2c"),
35833587
.key_size = sizeof(unsigned int),
35843588
.value_size = sizeof(struct pprint_mapv),
35853589
.key_type_id = 3, /* unsigned int */
@@ -3628,7 +3632,7 @@ static struct btf_raw_test pprint_test_template[] = {
36283632
BTF_ENUM_ENC(NAME_TBD, 2),
36293633
BTF_ENUM_ENC(NAME_TBD, 3),
36303634
/* struct pprint_mapv */ /* [16] */
3631-
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 8), 32),
3635+
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 10), 40),
36323636
BTF_MEMBER_ENC(NAME_TBD, 11, BTF_MEMBER_OFFSET(0, 0)), /* uint32_t ui32 */
36333637
BTF_MEMBER_ENC(NAME_TBD, 10, BTF_MEMBER_OFFSET(0, 32)), /* uint16_t ui16 */
36343638
BTF_MEMBER_ENC(NAME_TBD, 12, BTF_MEMBER_OFFSET(0, 64)), /* int32_t si32 */
@@ -3637,9 +3641,11 @@ static struct btf_raw_test pprint_test_template[] = {
36373641
BTF_MEMBER_ENC(NAME_TBD, 6, BTF_MEMBER_OFFSET(2, 126)), /* unused_bits2b */
36383642
BTF_MEMBER_ENC(0, 14, BTF_MEMBER_OFFSET(0, 128)), /* union (anon) */
36393643
BTF_MEMBER_ENC(NAME_TBD, 15, BTF_MEMBER_OFFSET(0, 192)), /* aenum */
3644+
BTF_MEMBER_ENC(NAME_TBD, 11, BTF_MEMBER_OFFSET(0, 224)), /* uint32_t ui32b */
3645+
BTF_MEMBER_ENC(NAME_TBD, 6, BTF_MEMBER_OFFSET(2, 256)), /* bits2c */
36403646
BTF_END_RAW,
36413647
},
3642-
BTF_STR_SEC("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum"),
3648+
BTF_STR_SEC("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum\0ui32b\0bits2c"),
36433649
.key_size = sizeof(unsigned int),
36443650
.value_size = sizeof(struct pprint_mapv),
36453651
.key_type_id = 3, /* unsigned int */
@@ -3690,7 +3696,7 @@ static struct btf_raw_test pprint_test_template[] = {
36903696
BTF_ENUM_ENC(NAME_TBD, 2),
36913697
BTF_ENUM_ENC(NAME_TBD, 3),
36923698
/* struct pprint_mapv */ /* [16] */
3693-
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 8), 32),
3699+
BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, 10), 40),
36943700
BTF_MEMBER_ENC(NAME_TBD, 11, BTF_MEMBER_OFFSET(0, 0)), /* uint32_t ui32 */
36953701
BTF_MEMBER_ENC(NAME_TBD, 10, BTF_MEMBER_OFFSET(0, 32)), /* uint16_t ui16 */
36963702
BTF_MEMBER_ENC(NAME_TBD, 12, BTF_MEMBER_OFFSET(0, 64)), /* int32_t si32 */
@@ -3699,13 +3705,15 @@ static struct btf_raw_test pprint_test_template[] = {
36993705
BTF_MEMBER_ENC(NAME_TBD, 19, BTF_MEMBER_OFFSET(2, 126)),/* unused_bits2b */
37003706
BTF_MEMBER_ENC(0, 14, BTF_MEMBER_OFFSET(0, 128)), /* union (anon) */
37013707
BTF_MEMBER_ENC(NAME_TBD, 15, BTF_MEMBER_OFFSET(0, 192)), /* aenum */
3708+
BTF_MEMBER_ENC(NAME_TBD, 11, BTF_MEMBER_OFFSET(0, 224)), /* uint32_t ui32b */
3709+
BTF_MEMBER_ENC(NAME_TBD, 17, BTF_MEMBER_OFFSET(2, 256)), /* bits2c */
37023710
/* typedef unsigned int ___int */ /* [17] */
37033711
BTF_TYPEDEF_ENC(NAME_TBD, 18),
37043712
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_VOLATILE, 0, 0), 6), /* [18] */
37053713
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), 15), /* [19] */
37063714
BTF_END_RAW,
37073715
},
3708-
BTF_STR_SEC("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum\0___int"),
3716+
BTF_STR_SEC("\0unsigned char\0unsigned short\0unsigned int\0int\0unsigned long long\0uint8_t\0uint16_t\0uint32_t\0int32_t\0uint64_t\0ui64\0ui8a\0ENUM_ZERO\0ENUM_ONE\0ENUM_TWO\0ENUM_THREE\0pprint_mapv\0ui32\0ui16\0si32\0unused_bits2a\0bits28\0unused_bits2b\0aenum\0ui32b\0bits2c\0___int"),
37093717
.key_size = sizeof(unsigned int),
37103718
.value_size = sizeof(struct pprint_mapv),
37113719
.key_type_id = 3, /* unsigned int */
@@ -3793,6 +3801,8 @@ static void set_pprint_mapv(struct pprint_mapv *v, uint32_t i,
37933801
v->unused_bits2b = 3;
37943802
v->ui64 = i;
37953803
v->aenum = i & 0x03;
3804+
v->ui32b = 4;
3805+
v->bits2c = 1;
37963806
v = (void *)v + rounded_value_size;
37973807
}
37983808
}
@@ -3955,7 +3965,8 @@ static int do_test_pprint(int test_num)
39553965

39563966
nexpected_line = snprintf(expected_line, sizeof(expected_line),
39573967
"%s%u: {%u,0,%d,0x%x,0x%x,0x%x,"
3958-
"{%lu|[%u,%u,%u,%u,%u,%u,%u,%u]},%s}\n",
3968+
"{%lu|[%u,%u,%u,%u,%u,%u,%u,%u]},%s,"
3969+
"%u,0x%x}\n",
39593970
percpu_map ? "\tcpu" : "",
39603971
percpu_map ? cpu : next_key,
39613972
cmapv->ui32, cmapv->si32,
@@ -3967,7 +3978,9 @@ static int do_test_pprint(int test_num)
39673978
cmapv->ui8a[2], cmapv->ui8a[3],
39683979
cmapv->ui8a[4], cmapv->ui8a[5],
39693980
cmapv->ui8a[6], cmapv->ui8a[7],
3970-
pprint_enum_str[cmapv->aenum]);
3981+
pprint_enum_str[cmapv->aenum],
3982+
cmapv->ui32b,
3983+
cmapv->bits2c);
39713984

39723985
err = check_line(expected_line, nexpected_line,
39733986
sizeof(expected_line), line);

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