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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2016 Facebook
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <linux/perf_event.h>
#include <errno.h>
#include <stdbool.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
#include "trace_helpers.h"
#define PRINT_RAW_ADDR 0
/* counts, stackmap */
static int map_fd[2];
static void print_ksym(__u64 addr)
{
struct ksym *sym;
if (!addr)
return;
sym = ksym_search(addr);
if (!sym) {
printf("ksym not found. Is kallsyms loaded?\n");
return;
}
if (PRINT_RAW_ADDR)
printf("%s/%llx;", sym->name, addr);
else
printf("%s;", sym->name);
}
#define TASK_COMM_LEN 16
struct key_t {
char waker[TASK_COMM_LEN];
char target[TASK_COMM_LEN];
__u32 wret;
__u32 tret;
};
static void print_stack(struct key_t *key, __u64 count)
{
__u64 ip[PERF_MAX_STACK_DEPTH] = {};
static bool warned;
int i;
printf("%s;", key->target);
if (bpf_map_lookup_elem(map_fd[1], &key->tret, ip) != 0) {
printf("---;");
} else {
for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
print_ksym(ip[i]);
}
printf("-;");
if (bpf_map_lookup_elem(map_fd[1], &key->wret, ip) != 0) {
printf("---;");
} else {
for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)
print_ksym(ip[i]);
}
printf(";%s %lld\n", key->waker, count);
if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) {
printf("stackmap collisions seen. Consider increasing size\n");
warned = true;
} else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) {
printf("err stackid %d %d\n", key->tret, key->wret);
}
}
static void print_stacks(int fd)
{
struct key_t key = {}, next_key;
__u64 value;
while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
bpf_map_lookup_elem(fd, &next_key, &value);
print_stack(&next_key, value);
key = next_key;
}
}
static void int_exit(int sig)
{
print_stacks(map_fd[0]);
exit(0);
}
int main(int argc, char **argv)
{
struct bpf_object *obj = NULL;
struct bpf_link *links[2];
struct bpf_program *prog;
int delay = 1, i = 0;
char filename[256];
if (load_kallsyms()) {
printf("failed to process /proc/kallsyms\n");
return 2;
}
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
obj = NULL;
goto cleanup;
}
/* load BPF program */
if (bpf_object__load(obj)) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
goto cleanup;
}
map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
if (map_fd[0] < 0 || map_fd[1] < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
bpf_object__for_each_program(prog, obj) {
links[i] = bpf_program__attach(prog);
if (libbpf_get_error(links[i])) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
links[i] = NULL;
goto cleanup;
}
i++;
}
if (argc > 1)
delay = atoi(argv[1]);
sleep(delay);
print_stacks(map_fd[0]);
cleanup:
for (i--; i >= 0; i--)
bpf_link__destroy(links[i]);
bpf_object__close(obj);
return 0;
}
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