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// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <pthread.h>
#include <sched.h>
#include <sys/socket.h>
#include <test_progs.h>
#include "bpf/libbpf_internal.h"
/* AddressSanitizer sometimes crashes due to data dereference below, due to
* this being mmap()'ed memory. Disable instrumentation with
* no_sanitize_address attribute
*/
__attribute__((no_sanitize_address))
static void on_sample(void *ctx, int cpu, void *data, __u32 size)
{
int cpu_data = *(int *)data, duration = 0;
cpu_set_t *cpu_seen = ctx;
if (cpu_data != cpu)
CHECK(cpu_data != cpu, "check_cpu_data",
"cpu_data %d != cpu %d\n", cpu_data, cpu);
CPU_SET(cpu, cpu_seen);
}
void test_perf_buffer(void)
{
int err, prog_fd, on_len, nr_on_cpus = 0, nr_cpus, i, duration = 0;
const char *prog_name = "kprobe/sys_nanosleep";
const char *file = "./test_perf_buffer.o";
struct perf_buffer_opts pb_opts = {};
struct bpf_map *perf_buf_map;
cpu_set_t cpu_set, cpu_seen;
struct bpf_program *prog;
struct bpf_object *obj;
struct perf_buffer *pb;
struct bpf_link *link;
bool *online;
nr_cpus = libbpf_num_possible_cpus();
if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
return;
err = parse_cpu_mask_file("/sys/devices/system/cpu/online",
&online, &on_len);
if (CHECK(err, "nr_on_cpus", "err %d\n", err))
return;
for (i = 0; i < on_len; i++)
if (online[i])
nr_on_cpus++;
/* load program */
err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno)) {
obj = NULL;
goto out_close;
}
prog = bpf_object__find_program_by_title(obj, prog_name);
if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
goto out_close;
/* load map */
perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map");
if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
goto out_close;
/* attach kprobe */
link = bpf_program__attach_kprobe(prog, false /* retprobe */,
SYS_NANOSLEEP_KPROBE_NAME);
if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
goto out_close;
/* set up perf buffer */
pb_opts.sample_cb = on_sample;
pb_opts.ctx = &cpu_seen;
pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
goto out_detach;
/* trigger kprobe on every CPU */
CPU_ZERO(&cpu_seen);
for (i = 0; i < nr_cpus; i++) {
if (i >= on_len || !online[i]) {
printf("skipping offline CPU #%d\n", i);
continue;
}
CPU_ZERO(&cpu_set);
CPU_SET(i, &cpu_set);
err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set),
&cpu_set);
if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
i, err))
goto out_detach;
usleep(1);
}
/* read perf buffer */
err = perf_buffer__poll(pb, 100);
if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
goto out_free_pb;
if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
"expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
goto out_free_pb;
out_free_pb:
perf_buffer__free(pb);
out_detach:
bpf_link__destroy(link);
out_close:
bpf_object__close(obj);
free(online);
}
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