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 "libbpf.h" 16 #include "bpf_load.h" 17 #include "trace_helpers.h" 18 19 #define PRINT_RAW_ADDR 0 20 21 static 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 41 struct key_t { 42 char waker[TASK_COMM_LEN]; 43 char target[TASK_COMM_LEN]; 44 __u32 wret; 45 __u32 tret; 46 }; 47 48 static 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 78 static 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 90 static void int_exit(int sig) 91 { 92 print_stacks(map_fd[0]); 93 exit(0); 94 } 95 96 int 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 } 125