1// SPDX-License-Identifier: GPL-2.0-only
  2/* Copyright (c) 2016 Facebook
  3 */
  4#include <stdio.h>
  5#include <unistd.h>
  6#include <stdlib.h>
  7#include <signal.h>
  8#include <linux/bpf.h>
  9#include <string.h>
 10#include <linux/perf_event.h>
 11#include <errno.h>
 12#include <assert.h>
 13#include <stdbool.h>
 14#include <sys/resource.h>
 15#include <bpf/libbpf.h>
 16#include "bpf_load.h"
 17#include "trace_helpers.h"
 18
 19#define PRINT_RAW_ADDR 0
 20
 21static void print_ksym(__u64 addr)
 22{
 23	struct ksym *sym;
 24
 25	if (!addr)
 26		return;
 27	sym = ksym_search(addr);
 28	if (!sym) {
 29		printf("ksym not found. Is kallsyms loaded?\n");
 30		return;
 31	}
 32
 33	if (PRINT_RAW_ADDR)
 34		printf("%s/%llx;", sym->name, addr);
 35	else
 36		printf("%s;", sym->name);
 37}
 38
 39#define TASK_COMM_LEN 16
 40
 41struct key_t {
 42	char waker[TASK_COMM_LEN];
 43	char target[TASK_COMM_LEN];
 44	__u32 wret;
 45	__u32 tret;
 46};
 47
 48static void print_stack(struct key_t *key, __u64 count)
 49{
 50	__u64 ip[PERF_MAX_STACK_DEPTH] = {};
 51	static bool warned;
 52	int i;
 53
 54	printf("%s;", key->target);
 55	if (bpf_map_lookup_elem(map_fd[3], &key->tret, ip) != 0) {
 56		printf("---;");
 57	} else {
 58		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
 59			print_ksym(ip[i]);
 60	}
 61	printf("-;");
 62	if (bpf_map_lookup_elem(map_fd[3], &key->wret, ip) != 0) {
 63		printf("---;");
 64	} else {
 65		for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)
 66			print_ksym(ip[i]);
 67	}
 68	printf(";%s %lld\n", key->waker, count);
 69
 70	if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) {
 71		printf("stackmap collisions seen. Consider increasing size\n");
 72		warned = true;
 73	} else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) {
 74		printf("err stackid %d %d\n", key->tret, key->wret);
 75	}
 76}
 77
 78static void print_stacks(int fd)
 79{
 80	struct key_t key = {}, next_key;
 81	__u64 value;
 82
 83	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
 84		bpf_map_lookup_elem(fd, &next_key, &value);
 85		print_stack(&next_key, value);
 86		key = next_key;
 87	}
 88}
 89
 90static void int_exit(int sig)
 91{
 92	print_stacks(map_fd[0]);
 93	exit(0);
 94}
 95
 96int main(int argc, char **argv)
 97{
 98	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 99	char filename[256];
100	int delay = 1;
101
102	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
103	setrlimit(RLIMIT_MEMLOCK, &r);
104
105	signal(SIGINT, int_exit);
106	signal(SIGTERM, int_exit);
107
108	if (load_kallsyms()) {
109		printf("failed to process /proc/kallsyms\n");
110		return 2;
111	}
112
113	if (load_bpf_file(filename)) {
114		printf("%s", bpf_log_buf);
115		return 1;
116	}
117
118	if (argc > 1)
119		delay = atoi(argv[1]);
120	sleep(delay);
121	print_stacks(map_fd[0]);
122
123	return 0;
124}