perf tools: Synthesize PERF_RECORD_* for loaded BPF programs

This patch synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for
BPF programs loaded before perf-record. This is achieved by gathering
information about all BPF programs via sys_bpf.

Committer notes:

Fix the build on some older systems such as amazonlinux:1 where it was
breaking with:

  util/bpf-event.c: In function 'perf_event__synthesize_one_bpf_prog':
  util/bpf-event.c:52:9: error: missing initializer for field 'type' of 'struct bpf_prog_info' [-Werror=missing-field-initializers]
    struct bpf_prog_info info = {};
           ^
  In file included from /git/linux/tools/lib/bpf/bpf.h:26:0,
                   from util/bpf-event.c:3:
  /git/linux/tools/include/uapi/linux/bpf.h:2699:8: note: 'type' declared here
    __u32 type;
          ^
  cc1: all warnings being treated as errors

Further fix on a centos:6 system:

  cc1: warnings being treated as errors
  util/bpf-event.c: In function 'perf_event__synthesize_one_bpf_prog':
  util/bpf-event.c:50: error: 'func_info_rec_size' may be used uninitialized in this function

The compiler is wrong, but to silence it, initialize that variable to
zero.

One more fix, this time for debian:experimental-x-mips, x-mips64 and
x-mipsel:

  util/bpf-event.c: In function 'perf_event__synthesize_one_bpf_prog':
  util/bpf-event.c:93:16: error: implicit declaration of function 'calloc' [-Werror=implicit-function-declaration]
     func_infos = calloc(sub_prog_cnt, func_info_rec_size);
                  ^~~~~~
  util/bpf-event.c:93:16: error: incompatible implicit declaration of built-in function 'calloc' [-Werror]
  util/bpf-event.c:93:16: note: include '<stdlib.h>' or provide a declaration of 'calloc'

Add the missing header.

Committer testing:

  # perf record --bpf-event sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.021 MB perf.data (7 samples) ]
  # perf report -D | grep PERF_RECORD_BPF_EVENT | nl
     1	0 0x4b10 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 13
     2	0 0x4c60 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 14
     3	0 0x4db0 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 15
     4	0 0x4f00 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 16
     5	0 0x5050 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 17
     6	0 0x51a0 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 18
     7	0 0x52f0 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 21
     8	0 0x5440 [0x18]: PERF_RECORD_BPF_EVENT bpf event with type 1, flags 0, id 22
  # bpftool prog
  13: cgroup_skb  tag 7be49e3934a125ba  gpl
	loaded_at 2019-01-19T09:09:43-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 13,14
  14: cgroup_skb  tag 2a142ef67aaad174  gpl
	loaded_at 2019-01-19T09:09:43-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 13,14
  15: cgroup_skb  tag 7be49e3934a125ba  gpl
	loaded_at 2019-01-19T09:09:43-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 15,16
  16: cgroup_skb  tag 2a142ef67aaad174  gpl
	loaded_at 2019-01-19T09:09:43-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 15,16
  17: cgroup_skb  tag 7be49e3934a125ba  gpl
	loaded_at 2019-01-19T09:09:44-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 17,18
  18: cgroup_skb  tag 2a142ef67aaad174  gpl
	loaded_at 2019-01-19T09:09:44-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 17,18
  21: cgroup_skb  tag 7be49e3934a125ba  gpl
	loaded_at 2019-01-19T09:09:45-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 21,22
  22: cgroup_skb  tag 2a142ef67aaad174  gpl
	loaded_at 2019-01-19T09:09:45-0300  uid 0
	xlated 296B  jited 229B  memlock 4096B  map_ids 21,22
  #

  # perf report -D | grep -B22 PERF_RECORD_KSYMBOL
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 ff 44 06 c0 ff ff ff ff  ......8..D......
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 37 62 65 34 39 65 33 39 33 34 61 31 32 35 62  _7be49e3934a125b
  .  0030:  61 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  a...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  7b e4 9e 39 34 a1 25 ba 00 00 00 00 00 00 00 00  {..94.%.........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x49d8 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc00644ff len 229 type 1 flags 0x0 name bpf_prog_7be49e3934a125ba
  --
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 48 6d 06 c0 ff ff ff ff  ......8.Hm......
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 32 61 31 34 32 65 66 36 37 61 61 61 64 31 37  _2a142ef67aaad17
  .  0030:  34 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  4...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  2a 14 2e f6 7a aa d1 74 00 00 00 00 00 00 00 00  *...z..t........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x4b28 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc0066d48 len 229 type 1 flags 0x0 name bpf_prog_2a142ef67aaad174
  --
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 04 cf 03 c0 ff ff ff ff  ......8.........
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 37 62 65 34 39 65 33 39 33 34 61 31 32 35 62  _7be49e3934a125b
  .  0030:  61 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  a...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  7b e4 9e 39 34 a1 25 ba 00 00 00 00 00 00 00 00  {..94.%.........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x4c78 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc003cf04 len 229 type 1 flags 0x0 name bpf_prog_7be49e3934a125ba
  --
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 96 28 04 c0 ff ff ff ff  ......8..(......
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 32 61 31 34 32 65 66 36 37 61 61 61 64 31 37  _2a142ef67aaad17
  .  0030:  34 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  4...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  2a 14 2e f6 7a aa d1 74 00 00 00 00 00 00 00 00  *...z..t........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x4dc8 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc0042896 len 229 type 1 flags 0x0 name bpf_prog_2a142ef67aaad174
  --
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 05 13 17 c0 ff ff ff ff  ......8.........
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 37 62 65 34 39 65 33 39 33 34 61 31 32 35 62  _7be49e3934a125b
  .  0030:  61 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  a...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  7b e4 9e 39 34 a1 25 ba 00 00 00 00 00 00 00 00  {..94.%.........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x4f18 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc0171305 len 229 type 1 flags 0x0 name bpf_prog_7be49e3934a125ba
  --
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 0a 8c 23 c0 ff ff ff ff  ......8...#.....
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 32 61 31 34 32 65 66 36 37 61 61 61 64 31 37  _2a142ef67aaad17
  .  0030:  34 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  4...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  2a 14 2e f6 7a aa d1 74 00 00 00 00 00 00 00 00  *...z..t........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x5068 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc0238c0a len 229 type 1 flags 0x0 name bpf_prog_2a142ef67aaad174
  --
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 2a a5 a4 c0 ff ff ff ff  ......8.*.......
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 37 62 65 34 39 65 33 39 33 34 61 31 32 35 62  _7be49e3934a125b
  .  0030:  61 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  a...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  7b e4 9e 39 34 a1 25 ba 00 00 00 00 00 00 00 00  {..94.%.........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x51b8 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc0a4a52a len 229 type 1 flags 0x0 name bpf_prog_7be49e3934a125ba
  --
  . ... raw event: size 312 bytes
  .  0000:  11 00 00 00 00 00 38 01 9b c9 a4 c0 ff ff ff ff  ......8.........
  .  0010:  e5 00 00 00 01 00 00 00 62 70 66 5f 70 72 6f 67  ........bpf_prog
  .  0020:  5f 32 61 31 34 32 65 66 36 37 61 61 61 64 31 37  _2a142ef67aaad17
  .  0030:  34 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  4...............
   <SNIP zeroes>
  .  0110:  00 00 00 00 00 00 00 00 21 00 00 00 00 00 00 00  ........!.......
  .  0120:  2a 14 2e f6 7a aa d1 74 00 00 00 00 00 00 00 00  *...z..t........
  .  0130:  00 00 00 00 00 00 00 00                          ........

  0 0x5308 [0x138]: PERF_RECORD_KSYMBOL ksymbol event with addr ffffffffc0a4c99b len 229 type 1 flags 0x0 name bpf_prog_2a142ef67aaad174

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-8-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Song Liu 2019-01-17 08:15:19 -08:00 committed by Arnaldo Carvalho de Melo
parent 45178a928a
commit 7b612e291a
3 changed files with 264 additions and 0 deletions

View File

@ -41,6 +41,7 @@
#include "util/perf-hooks.h"
#include "util/time-utils.h"
#include "util/units.h"
#include "util/bpf-event.h"
#include "asm/bug.h"
#include <errno.h>
@ -1082,6 +1083,11 @@ static int record__synthesize(struct record *rec, bool tail)
return err;
}
err = perf_event__synthesize_bpf_events(tool, process_synthesized_event,
machine, opts);
if (err < 0)
pr_warning("Couldn't synthesize bpf events.\n");
err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->threads,
process_synthesized_event, opts->sample_address,
1);

View File

@ -1,10 +1,25 @@
// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <stdlib.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <linux/btf.h>
#include "bpf-event.h"
#include "debug.h"
#include "symbol.h"
#define ptr_to_u64(ptr) ((__u64)(unsigned long)(ptr))
static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
{
int ret = 0;
size_t i;
for (i = 0; i < len; i++)
ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
return ret;
}
int machine__process_bpf_event(struct machine *machine __maybe_unused,
union perf_event *event,
struct perf_sample *sample __maybe_unused)
@ -13,3 +28,230 @@ int machine__process_bpf_event(struct machine *machine __maybe_unused,
perf_event__fprintf_bpf_event(event, stdout);
return 0;
}
/*
* Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
* program. One PERF_RECORD_BPF_EVENT is generated for the program. And
* one PERF_RECORD_KSYMBOL is generated for each sub program.
*
* Returns:
* 0 for success;
* -1 for failures;
* -2 for lack of kernel support.
*/
static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine,
int fd,
union perf_event *event,
struct record_opts *opts)
{
struct ksymbol_event *ksymbol_event = &event->ksymbol_event;
struct bpf_event *bpf_event = &event->bpf_event;
u32 sub_prog_cnt, i, func_info_rec_size = 0;
u8 (*prog_tags)[BPF_TAG_SIZE] = NULL;
struct bpf_prog_info info = { .type = 0, };
u32 info_len = sizeof(info);
void *func_infos = NULL;
u64 *prog_addrs = NULL;
struct btf *btf = NULL;
u32 *prog_lens = NULL;
bool has_btf = false;
char errbuf[512];
int err = 0;
/* Call bpf_obj_get_info_by_fd() to get sizes of arrays */
err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
if (err) {
pr_debug("%s: failed to get BPF program info: %s, aborting\n",
__func__, str_error_r(errno, errbuf, sizeof(errbuf)));
return -1;
}
if (info_len < offsetof(struct bpf_prog_info, prog_tags)) {
pr_debug("%s: the kernel is too old, aborting\n", __func__);
return -2;
}
/* number of ksyms, func_lengths, and tags should match */
sub_prog_cnt = info.nr_jited_ksyms;
if (sub_prog_cnt != info.nr_prog_tags ||
sub_prog_cnt != info.nr_jited_func_lens)
return -1;
/* check BTF func info support */
if (info.btf_id && info.nr_func_info && info.func_info_rec_size) {
/* btf func info number should be same as sub_prog_cnt */
if (sub_prog_cnt != info.nr_func_info) {
pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
return -1;
}
if (btf__get_from_id(info.btf_id, &btf)) {
pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info.btf_id);
return -1;
}
func_info_rec_size = info.func_info_rec_size;
func_infos = calloc(sub_prog_cnt, func_info_rec_size);
if (!func_infos) {
pr_debug("%s: failed to allocate memory for func_infos, aborting\n", __func__);
return -1;
}
has_btf = true;
}
/*
* We need address, length, and tag for each sub program.
* Allocate memory and call bpf_obj_get_info_by_fd() again
*/
prog_addrs = calloc(sub_prog_cnt, sizeof(u64));
if (!prog_addrs) {
pr_debug("%s: failed to allocate memory for prog_addrs, aborting\n", __func__);
goto out;
}
prog_lens = calloc(sub_prog_cnt, sizeof(u32));
if (!prog_lens) {
pr_debug("%s: failed to allocate memory for prog_lens, aborting\n", __func__);
goto out;
}
prog_tags = calloc(sub_prog_cnt, BPF_TAG_SIZE);
if (!prog_tags) {
pr_debug("%s: failed to allocate memory for prog_tags, aborting\n", __func__);
goto out;
}
memset(&info, 0, sizeof(info));
info.nr_jited_ksyms = sub_prog_cnt;
info.nr_jited_func_lens = sub_prog_cnt;
info.nr_prog_tags = sub_prog_cnt;
info.jited_ksyms = ptr_to_u64(prog_addrs);
info.jited_func_lens = ptr_to_u64(prog_lens);
info.prog_tags = ptr_to_u64(prog_tags);
info_len = sizeof(info);
if (has_btf) {
info.nr_func_info = sub_prog_cnt;
info.func_info_rec_size = func_info_rec_size;
info.func_info = ptr_to_u64(func_infos);
}
err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
if (err) {
pr_debug("%s: failed to get BPF program info, aborting\n", __func__);
goto out;
}
/* Synthesize PERF_RECORD_KSYMBOL */
for (i = 0; i < sub_prog_cnt; i++) {
const struct bpf_func_info *finfo;
const char *short_name = NULL;
const struct btf_type *t;
int name_len;
*ksymbol_event = (struct ksymbol_event){
.header = {
.type = PERF_RECORD_KSYMBOL,
.size = sizeof(struct ksymbol_event),
},
.addr = prog_addrs[i],
.len = prog_lens[i],
.ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
.flags = 0,
};
name_len = snprintf(ksymbol_event->name, KSYM_NAME_LEN,
"bpf_prog_");
name_len += snprintf_hex(ksymbol_event->name + name_len,
KSYM_NAME_LEN - name_len,
prog_tags[i], BPF_TAG_SIZE);
if (has_btf) {
finfo = func_infos + i * info.func_info_rec_size;
t = btf__type_by_id(btf, finfo->type_id);
short_name = btf__name_by_offset(btf, t->name_off);
} else if (i == 0 && sub_prog_cnt == 1) {
/* no subprog */
if (info.name[0])
short_name = info.name;
} else
short_name = "F";
if (short_name)
name_len += snprintf(ksymbol_event->name + name_len,
KSYM_NAME_LEN - name_len,
"_%s", short_name);
ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
sizeof(u64));
err = perf_tool__process_synth_event(tool, event,
machine, process);
}
/* Synthesize PERF_RECORD_BPF_EVENT */
if (opts->bpf_event) {
*bpf_event = (struct bpf_event){
.header = {
.type = PERF_RECORD_BPF_EVENT,
.size = sizeof(struct bpf_event),
},
.type = PERF_BPF_EVENT_PROG_LOAD,
.flags = 0,
.id = info.id,
};
memcpy(bpf_event->tag, prog_tags[i], BPF_TAG_SIZE);
err = perf_tool__process_synth_event(tool, event,
machine, process);
}
out:
free(prog_tags);
free(prog_lens);
free(prog_addrs);
free(func_infos);
free(btf);
return err ? -1 : 0;
}
int perf_event__synthesize_bpf_events(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine,
struct record_opts *opts)
{
union perf_event *event;
__u32 id = 0;
int err;
int fd;
event = malloc(sizeof(event->bpf_event) + KSYM_NAME_LEN);
if (!event)
return -1;
while (true) {
err = bpf_prog_get_next_id(id, &id);
if (err) {
if (errno == ENOENT) {
err = 0;
break;
}
pr_debug("%s: can't get next program: %s%s",
__func__, strerror(errno),
errno == EINVAL ? " -- kernel too old?" : "");
/* don't report error on old kernel */
err = (errno == EINVAL) ? 0 : -1;
break;
}
fd = bpf_prog_get_fd_by_id(id);
if (fd < 0) {
pr_debug("%s: failed to get fd for prog_id %u\n",
__func__, id);
continue;
}
err = perf_event__synthesize_one_bpf_prog(tool, process,
machine, fd,
event, opts);
close(fd);
if (err) {
/* do not return error for old kernel */
if (err == -2)
err = 0;
break;
}
}
free(event);
return err;
}

View File

@ -3,14 +3,22 @@
#define __PERF_BPF_EVENT_H
#include <linux/compiler.h>
#include "event.h"
struct machine;
union perf_event;
struct perf_sample;
struct perf_tool;
struct record_opts;
#ifdef HAVE_LIBBPF_SUPPORT
int machine__process_bpf_event(struct machine *machine, union perf_event *event,
struct perf_sample *sample);
int perf_event__synthesize_bpf_events(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine,
struct record_opts *opts);
#else
static inline int machine__process_bpf_event(struct machine *machine __maybe_unused,
union perf_event *event __maybe_unused,
@ -18,5 +26,13 @@ static inline int machine__process_bpf_event(struct machine *machine __maybe_unu
{
return 0;
}
static inline int perf_event__synthesize_bpf_events(struct perf_tool *tool __maybe_unused,
perf_event__handler_t process __maybe_unused,
struct machine *machine __maybe_unused,
struct record_opts *opts __maybe_unused)
{
return 0;
}
#endif // HAVE_LIBBPF_SUPPORT
#endif