From: "Jose E. Marchesi" <jose.marchesi@oracle.com>
To: James Hilliard <james.hilliard1@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>, bpf <bpf@vger.kernel.org>
Subject: Re: bpftool gen object doesn't handle GCC built BPF ELF files
Date: Fri, 08 Jul 2022 13:55:58 +0200 [thread overview]
Message-ID: <87let3es35.fsf@oracle.com> (raw)
In-Reply-To: <CADvTj4rfDAFj0MAVyo=jaBG85MTgHcXi75_cRsby1LXTk7FgfQ@mail.gmail.com> (James Hilliard's message of "Wed, 6 Jul 2022 11:49:01 -0600")
> On Wed, Jul 6, 2022 at 11:20 AM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
>>
>> On Wed, Jul 6, 2022 at 10:13 AM James Hilliard
>> <james.hilliard1@gmail.com> wrote:
>> >
>> > Note I'm testing with the following patches:
>> > https://lore.kernel.org/bpf/20220706111839.1247911-1-james.hilliard1@gmail.com/
>> > https://lore.kernel.org/bpf/20220706140623.2917858-1-james.hilliard1@gmail.com/
>> >
>> > It would appear there's some compatibility issues with bpftool gen and
>> > GCC, not sure what side though is wrong here:
>> > /home/buildroot/buildroot/output/per-package/systemd/host/sbin/bpftool
>> > gen object src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.o
>> > src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.unstripped.o
>> > libbpf: failed to find BTF info for global/extern symbol 'sd_restrictif_i'
>> > Error: failed to link
>> > 'src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.unstripped.o':
>> > Unknown error -2 (-2)
>> >
>> > Relevant difference seems to be this:
>> > GCC:
>> > [55] FUNC 'sd_restrictif_i' type_id=47 linkage=static
>> > Clang:
>> > [27] FUNC 'sd_restrictif_i' type_id=26 linkage=global
>> >
>>
>> GCC is wrong, clearly. This function is global ([0]) and libbpf
>> expects it to be marked as such in BTF.
>
> Does this invocation look correct?
> /home/buildroot/buildroot/output/per-package/systemd/host/bin/bpf-gcc
> -O2 -mkernel=5.2 -mcpu=v3 -mco-re -gbtf -r -std=gnu11 -D__x86_64__
> -mlittle-endian -I. -idirafter
> /home/buildroot/buildroot/output/per-package/systemd/host/x86_64-buildroot-linux-gnu/sysroot/usr/include
> ../src/core/bpf/restrict_fs/restrict-fs.bpf.c -o
> src/core/bpf/restrict_fs/restrict-fs.bpf.unstripped.o
Hmm, why linking a relocatable ELF instead of just using a compiled
object (with -c)?
> I've also tried without the -r(relocatable object) flag but that gives
> a different error:
> /home/buildroot/buildroot/output/per-package/systemd/host/sbin/bpftool
> gen object src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.o
> src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.unstripped.o
> libbpf: unsupported kind of ELF file
> src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.unstripped.o: no
> error
> Error: failed to link
> 'src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.unstripped.o':
> Unknown error -95 (-95)
>
> GCC without relocatable flag:
> [1] INT 'signed char' size=1 bits_offset=0 nr_bits=8 encoding=UNKN
> [2] INT 'unsigned char' size=1 bits_offset=0 nr_bits=8 encoding=CHAR
> [3] TYPEDEF '__u8' type_id=2
> [4] CONST '(anon)' type_id=3
> [5] VOLATILE '(anon)' type_id=4
> [6] INT 'short int' size=2 bits_offset=0 nr_bits=16 encoding=SIGNED
> [7] INT 'short unsigned int' size=2 bits_offset=0 nr_bits=16 encoding=(none)
> [8] TYPEDEF '__u16' type_id=7
> [9] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
> [10] TYPEDEF '__s32' type_id=9
> [11] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)
> [12] TYPEDEF '__u32' type_id=11
> [13] INT 'long long int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED
> [14] INT 'long long unsigned int' size=8 bits_offset=0 nr_bits=64
> encoding=(none)
> [15] TYPEDEF '__u64' type_id=14
> [16] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> [17] INT 'long int' size=8 bits_offset=0 nr_bits=64 encoding=SIGNED
> [18] INT 'char' size=1 bits_offset=0 nr_bits=8 encoding=UNKN
> [19] CONST '(anon)' type_id=18
> [20] TYPEDEF '__be16' type_id=8
> [21] TYPEDEF '__be32' type_id=12
> [22] ENUM 'bpf_map_type' encoding=UNSIGNED size=4 vlen=31
> 'BPF_MAP_TYPE_UNSPEC' val=0
> 'BPF_MAP_TYPE_HASH' val=1
> 'BPF_MAP_TYPE_ARRAY' val=2
> 'BPF_MAP_TYPE_PROG_ARRAY' val=3
> 'BPF_MAP_TYPE_PERF_EVENT_ARRAY' val=4
> 'BPF_MAP_TYPE_PERCPU_HASH' val=5
> 'BPF_MAP_TYPE_PERCPU_ARRAY' val=6
> 'BPF_MAP_TYPE_STACK_TRACE' val=7
> 'BPF_MAP_TYPE_CGROUP_ARRAY' val=8
> 'BPF_MAP_TYPE_LRU_HASH' val=9
> 'BPF_MAP_TYPE_LRU_PERCPU_HASH' val=10
> 'BPF_MAP_TYPE_LPM_TRIE' val=11
> 'BPF_MAP_TYPE_ARRAY_OF_MAPS' val=12
> 'BPF_MAP_TYPE_HASH_OF_MAPS' val=13
> 'BPF_MAP_TYPE_DEVMAP' val=14
> 'BPF_MAP_TYPE_SOCKMAP' val=15
> 'BPF_MAP_TYPE_CPUMAP' val=16
> 'BPF_MAP_TYPE_XSKMAP' val=17
> 'BPF_MAP_TYPE_SOCKHASH' val=18
> 'BPF_MAP_TYPE_CGROUP_STORAGE' val=19
> 'BPF_MAP_TYPE_REUSEPORT_SOCKARRAY' val=20
> 'BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE' val=21
> 'BPF_MAP_TYPE_QUEUE' val=22
> 'BPF_MAP_TYPE_STACK' val=23
> 'BPF_MAP_TYPE_SK_STORAGE' val=24
> 'BPF_MAP_TYPE_DEVMAP_HASH' val=25
> 'BPF_MAP_TYPE_STRUCT_OPS' val=26
> 'BPF_MAP_TYPE_RINGBUF' val=27
> 'BPF_MAP_TYPE_INODE_STORAGE' val=28
> 'BPF_MAP_TYPE_TASK_STORAGE' val=29
> 'BPF_MAP_TYPE_BLOOM_FILTER' val=30
> [23] UNION '(anon)' size=8 vlen=1
> 'flow_keys' type_id=29 bits_offset=0
> [24] STRUCT 'bpf_flow_keys' size=56 vlen=13
> 'nhoff' type_id=8 bits_offset=0
> 'thoff' type_id=8 bits_offset=16
> 'addr_proto' type_id=8 bits_offset=32
> 'is_frag' type_id=3 bits_offset=48
> 'is_first_frag' type_id=3 bits_offset=56
> 'is_encap' type_id=3 bits_offset=64
> 'ip_proto' type_id=3 bits_offset=72
> 'n_proto' type_id=20 bits_offset=80
> 'sport' type_id=20 bits_offset=96
> 'dport' type_id=20 bits_offset=112
> '(anon)' type_id=25 bits_offset=128
> 'flags' type_id=12 bits_offset=384
> 'flow_label' type_id=21 bits_offset=416
> [25] UNION '(anon)' size=32 vlen=2
> '(anon)' type_id=26 bits_offset=0
> '(anon)' type_id=27 bits_offset=0
> [26] STRUCT '(anon)' size=8 vlen=2
> 'ipv4_src' type_id=21 bits_offset=0
> 'ipv4_dst' type_id=21 bits_offset=32
> [27] STRUCT '(anon)' size=32 vlen=2
> 'ipv6_src' type_id=28 bits_offset=0
> 'ipv6_dst' type_id=28 bits_offset=128
> [28] ARRAY '(anon)' type_id=12 index_type_id=16 nr_elems=4
> [29] PTR '(anon)' type_id=24
> [30] UNION '(anon)' size=8 vlen=1
> 'sk' type_id=32 bits_offset=0
> [31] STRUCT 'bpf_sock' size=80 vlen=14
> 'bound_dev_if' type_id=12 bits_offset=0
> 'family' type_id=12 bits_offset=32
> 'type' type_id=12 bits_offset=64
> 'protocol' type_id=12 bits_offset=96
> 'mark' type_id=12 bits_offset=128
> 'priority' type_id=12 bits_offset=160
> 'src_ip4' type_id=12 bits_offset=192
> 'src_ip6' type_id=28 bits_offset=224
> 'src_port' type_id=12 bits_offset=352
> 'dst_port' type_id=20 bits_offset=384
> 'dst_ip4' type_id=12 bits_offset=416
> 'dst_ip6' type_id=28 bits_offset=448
> 'state' type_id=12 bits_offset=576
> 'rx_queue_mapping' type_id=10 bits_offset=608
> [32] PTR '(anon)' type_id=31
> [33] STRUCT '__sk_buff' size=192 vlen=33
> 'len' type_id=12 bits_offset=0
> 'pkt_type' type_id=12 bits_offset=32
> 'mark' type_id=12 bits_offset=64
> 'queue_mapping' type_id=12 bits_offset=96
> 'protocol' type_id=12 bits_offset=128
> 'vlan_present' type_id=12 bits_offset=160
> 'vlan_tci' type_id=12 bits_offset=192
> 'vlan_proto' type_id=12 bits_offset=224
> 'priority' type_id=12 bits_offset=256
> 'ingress_ifindex' type_id=12 bits_offset=288
> 'ifindex' type_id=12 bits_offset=320
> 'tc_index' type_id=12 bits_offset=352
> 'cb' type_id=34 bits_offset=384
> 'hash' type_id=12 bits_offset=544
> 'tc_classid' type_id=12 bits_offset=576
> 'data' type_id=12 bits_offset=608
> 'data_end' type_id=12 bits_offset=640
> 'napi_id' type_id=12 bits_offset=672
> 'family' type_id=12 bits_offset=704
> 'remote_ip4' type_id=12 bits_offset=736
> 'local_ip4' type_id=12 bits_offset=768
> 'remote_ip6' type_id=28 bits_offset=800
> 'local_ip6' type_id=28 bits_offset=928
> 'remote_port' type_id=12 bits_offset=1056
> 'local_port' type_id=12 bits_offset=1088
> 'data_meta' type_id=12 bits_offset=1120
> '(anon)' type_id=23 bits_offset=1152
> 'tstamp' type_id=15 bits_offset=1216
> 'wire_len' type_id=12 bits_offset=1280
> 'gso_segs' type_id=12 bits_offset=1312
> '(anon)' type_id=30 bits_offset=1344
> 'gso_size' type_id=12 bits_offset=1408
> 'hwtstamp' type_id=15 bits_offset=1472
> [34] ARRAY '(anon)' type_id=12 index_type_id=16 nr_elems=5
> [35] CONST '(anon)' type_id=33
> [36] PTR '(anon)' type_id=0
> [37] STRUCT '(anon)' size=24 vlen=3
> 'type' type_id=39 bits_offset=0
> 'key' type_id=40 bits_offset=64
> 'value' type_id=41 bits_offset=128
> [38] ARRAY '(anon)' type_id=9 index_type_id=16 nr_elems=1
> [39] PTR '(anon)' type_id=38
> [40] PTR '(anon)' type_id=12
> [41] PTR '(anon)' type_id=3
> [42] ARRAY '(anon)' type_id=19 index_type_id=16 nr_elems=18
> [43] CONST '(anon)' type_id=42
> [44] FUNC_PROTO '(anon)' ret_type_id=36 vlen=2
> '(anon)' type_id=36
> '(anon)' type_id=46
> [45] CONST '(anon)' type_id=0
> [46] PTR '(anon)' type_id=45
> [47] FUNC_PROTO '(anon)' ret_type_id=9 vlen=1
> 'sk' type_id=48
> [48] PTR '(anon)' type_id=35
> [49] FUNC_PROTO '(anon)' ret_type_id=9 vlen=1
> 'sk' type_id=48
> [50] FUNC_PROTO '(anon)' ret_type_id=9 vlen=1
> 'sk' type_id=48
> [51] VAR 'is_allow_list' type_id=5, linkage=global
> [52] VAR '_license' type_id=43, linkage=static
> [53] VAR 'sd_restrictif' type_id=37, linkage=global
> [54] FUNC 'bpf_map_lookup_elem' type_id=44 linkage=static
> [55] FUNC 'sd_restrictif_i' type_id=47 linkage=static
> [56] FUNC 'sd_restrictif_e' type_id=49 linkage=static
> [57] FUNC 'restrict_network_interfaces_impl' type_id=50 linkage=static
> [58] DATASEC 'license' size=0 vlen=1
> type_id=52 offset=0 size=18 (VAR '_license')
> [59] DATASEC '.maps' size=0 vlen=1
> type_id=53 offset=0 size=24 (VAR 'sd_restrictif')
> [60] DATASEC '.data' size=0 vlen=1
> type_id=51 offset=0 size=1 (VAR 'is_allow_list')
>
>>
>> https://github.com/systemd/systemd/blob/main/src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.c#L42-L50
>>
>>
>> > GCC:
>> >
>> > [1] INT 'signed char' size=1 bits_offset=0 nr_bits=8 encoding=UNKN
>> > [2] INT 'unsigned char' size=1 bits_offset=0 nr_bits=8 encoding=CHAR
>> > [3] TYPEDEF '__u8' type_id=2
>> > [4] CONST '(anon)' type_id=3
>>
>> [...]
next prev parent reply other threads:[~2022-07-08 11:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-06 17:11 bpftool gen object doesn't handle GCC built BPF ELF files James Hilliard
2022-07-06 17:20 ` Andrii Nakryiko
2022-07-06 17:49 ` James Hilliard
2022-07-08 11:55 ` Jose E. Marchesi [this message]
2022-07-08 12:23 ` James Hilliard
2022-07-08 13:46 ` Jose E. Marchesi
2022-07-08 13:53 ` James Hilliard
2022-07-08 14:39 ` Jose E. Marchesi
2022-07-08 14:51 ` Jose E. Marchesi
2022-07-08 18:33 ` Jose E. Marchesi
2022-07-08 20:59 ` James Hilliard
2022-07-09 17:24 ` Jose E. Marchesi
2022-07-09 17:28 ` James Hilliard
2022-07-09 20:20 ` Jose E. Marchesi
2022-07-09 20:32 ` James Hilliard
2022-07-09 20:39 ` James Hilliard
2022-07-09 22:41 ` Jose E. Marchesi
2022-07-09 22:54 ` James Hilliard
2022-07-10 9:38 ` Jose E. Marchesi
2022-07-10 12:16 ` James Hilliard
2022-07-10 13:06 ` Jose E. Marchesi
2022-07-10 19:49 ` Jose E. Marchesi
2022-07-10 20:22 ` Jose E. Marchesi
2022-07-11 1:55 ` Jose E. Marchesi
[not found] ` <CADvTj4o-36iuru665BW0XnEauXBeszW438QTtpt4_VUEjf5nXg@mail.gmail.com>
2022-08-01 22:51 ` Andrii Nakryiko
2022-08-01 23:35 ` James Hilliard
2022-08-02 21:28 ` Andrii Nakryiko
2022-08-02 22:05 ` James Hilliard
2022-08-03 0:29 ` Andrii Nakryiko
2022-08-03 1:49 ` James Hilliard
2022-08-03 16:57 ` Andrii Nakryiko
2022-08-03 19:24 ` James Hilliard
2022-09-30 21:52 ` James Hilliard
2022-09-30 22:50 ` Andrii Nakryiko
2022-08-04 17:29 ` Alexei Starovoitov
2022-08-02 15:57 ` Jose E. Marchesi
2022-07-12 0:34 ` Indu Bhagat
2022-07-13 4:28 ` Yonghong Song
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