1 /* Copyright (c) 2016 Facebook 2 * 3 * This program is free software; you can redistribute it and/or 4 * modify it under the terms of version 2 of the GNU General Public 5 * License as published by the Free Software Foundation. 6 */ 7 #include <stdio.h> 8 #include <unistd.h> 9 #include <stdlib.h> 10 #include <signal.h> 11 #include <linux/bpf.h> 12 #include <string.h> 13 #include <linux/perf_event.h> 14 #include <errno.h> 15 #include <assert.h> 16 #include <stdbool.h> 17 #include <sys/resource.h> 18 #include "libbpf.h" 19 #include "bpf_load.h" 20 #include "trace_helpers.h" 21 22 #define PRINT_RAW_ADDR 0 23 24 static void print_ksym(__u64 addr) 25 { 26 struct ksym *sym; 27 28 if (!addr) 29 return; 30 sym = ksym_search(addr); 31 if (PRINT_RAW_ADDR) 32 printf("%s/%llx;", sym->name, addr); 33 else 34 printf("%s;", sym->name); 35 } 36 37 #define TASK_COMM_LEN 16 38 39 struct key_t { 40 char waker[TASK_COMM_LEN]; 41 char target[TASK_COMM_LEN]; 42 __u32 wret; 43 __u32 tret; 44 }; 45 46 static void print_stack(struct key_t *key, __u64 count) 47 { 48 __u64 ip[PERF_MAX_STACK_DEPTH] = {}; 49 static bool warned; 50 int i; 51 52 printf("%s;", key->target); 53 if (bpf_map_lookup_elem(map_fd[3], &key->tret, ip) != 0) { 54 printf("---;"); 55 } else { 56 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) 57 print_ksym(ip[i]); 58 } 59 printf("-;"); 60 if (bpf_map_lookup_elem(map_fd[3], &key->wret, ip) != 0) { 61 printf("---;"); 62 } else { 63 for (i = 0; i < PERF_MAX_STACK_DEPTH; i++) 64 print_ksym(ip[i]); 65 } 66 printf(";%s %lld\n", key->waker, count); 67 68 if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) { 69 printf("stackmap collisions seen. Consider increasing size\n"); 70 warned = true; 71 } else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) { 72 printf("err stackid %d %d\n", key->tret, key->wret); 73 } 74 } 75 76 static void print_stacks(int fd) 77 { 78 struct key_t key = {}, next_key; 79 __u64 value; 80 81 while (bpf_map_get_next_key(fd, &key, &next_key) == 0) { 82 bpf_map_lookup_elem(fd, &next_key, &value); 83 print_stack(&next_key, value); 84 key = next_key; 85 } 86 } 87 88 static void int_exit(int sig) 89 { 90 print_stacks(map_fd[0]); 91 exit(0); 92 } 93 94 int main(int argc, char **argv) 95 { 96 struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; 97 char filename[256]; 98 int delay = 1; 99 100 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 101 setrlimit(RLIMIT_MEMLOCK, &r); 102 103 signal(SIGINT, int_exit); 104 signal(SIGTERM, int_exit); 105 106 if (load_kallsyms()) { 107 printf("failed to process /proc/kallsyms\n"); 108 return 2; 109 } 110 111 if (load_bpf_file(filename)) { 112 printf("%s", bpf_log_buf); 113 return 1; 114 } 115 116 if (argc > 1) 117 delay = atoi(argv[1]); 118 sleep(delay); 119 print_stacks(map_fd[0]); 120 121 return 0; 122 } 123