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