1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Test backward bit in event attribute, read ring buffer from end to 4 * beginning 5 */ 6 7 #include <evlist.h> 8 #include <sys/prctl.h> 9 #include "record.h" 10 #include "tests.h" 11 #include "debug.h" 12 #include "parse-events.h" 13 #include "util/mmap.h" 14 #include <errno.h> 15 #include <linux/string.h> 16 17 #define NR_ITERS 111 18 19 static void testcase(void) 20 { 21 int i; 22 23 for (i = 0; i < NR_ITERS; i++) { 24 char proc_name[15]; 25 26 snprintf(proc_name, sizeof(proc_name), "p:%d\n", i); 27 prctl(PR_SET_NAME, proc_name); 28 } 29 } 30 31 static int count_samples(struct evlist *evlist, int *sample_count, 32 int *comm_count) 33 { 34 int i; 35 36 for (i = 0; i < evlist->core.nr_mmaps; i++) { 37 struct mmap *map = &evlist->overwrite_mmap[i]; 38 union perf_event *event; 39 40 perf_mmap__read_init(map); 41 while ((event = perf_mmap__read_event(map)) != NULL) { 42 const u32 type = event->header.type; 43 44 switch (type) { 45 case PERF_RECORD_SAMPLE: 46 (*sample_count)++; 47 break; 48 case PERF_RECORD_COMM: 49 (*comm_count)++; 50 break; 51 default: 52 pr_err("Unexpected record of type %d\n", type); 53 return TEST_FAIL; 54 } 55 } 56 perf_mmap__read_done(map); 57 } 58 return TEST_OK; 59 } 60 61 static int do_test(struct evlist *evlist, int mmap_pages, 62 int *sample_count, int *comm_count) 63 { 64 int err; 65 char sbuf[STRERR_BUFSIZE]; 66 67 err = evlist__mmap(evlist, mmap_pages); 68 if (err < 0) { 69 pr_debug("evlist__mmap: %s\n", 70 str_error_r(errno, sbuf, sizeof(sbuf))); 71 return TEST_FAIL; 72 } 73 74 evlist__enable(evlist); 75 testcase(); 76 evlist__disable(evlist); 77 78 err = count_samples(evlist, sample_count, comm_count); 79 evlist__munmap(evlist); 80 return err; 81 } 82 83 84 int test__backward_ring_buffer(struct test *test __maybe_unused, int subtest __maybe_unused) 85 { 86 int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0; 87 char pid[16], sbuf[STRERR_BUFSIZE]; 88 struct evlist *evlist; 89 struct evsel *evsel __maybe_unused; 90 struct parse_events_error parse_error; 91 struct record_opts opts = { 92 .target = { 93 .uid = UINT_MAX, 94 .uses_mmap = true, 95 }, 96 .freq = 0, 97 .mmap_pages = 256, 98 .default_interval = 1, 99 }; 100 101 snprintf(pid, sizeof(pid), "%d", getpid()); 102 pid[sizeof(pid) - 1] = '\0'; 103 opts.target.tid = opts.target.pid = pid; 104 105 evlist = evlist__new(); 106 if (!evlist) { 107 pr_debug("Not enough memory to create evlist\n"); 108 return TEST_FAIL; 109 } 110 111 err = perf_evlist__create_maps(evlist, &opts.target); 112 if (err < 0) { 113 pr_debug("Not enough memory to create thread/cpu maps\n"); 114 goto out_delete_evlist; 115 } 116 117 bzero(&parse_error, sizeof(parse_error)); 118 /* 119 * Set backward bit, ring buffer should be writing from end. Record 120 * it in aux evlist 121 */ 122 err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error); 123 if (err) { 124 pr_debug("Failed to parse tracepoint event, try use root\n"); 125 ret = TEST_SKIP; 126 goto out_delete_evlist; 127 } 128 129 perf_evlist__config(evlist, &opts, NULL); 130 131 err = evlist__open(evlist); 132 if (err < 0) { 133 pr_debug("perf_evlist__open: %s\n", 134 str_error_r(errno, sbuf, sizeof(sbuf))); 135 goto out_delete_evlist; 136 } 137 138 ret = TEST_FAIL; 139 err = do_test(evlist, opts.mmap_pages, &sample_count, 140 &comm_count); 141 if (err != TEST_OK) 142 goto out_delete_evlist; 143 144 if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) { 145 pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n", 146 sample_count, comm_count); 147 goto out_delete_evlist; 148 } 149 150 err = do_test(evlist, 1, &sample_count, &comm_count); 151 if (err != TEST_OK) 152 goto out_delete_evlist; 153 154 ret = TEST_OK; 155 out_delete_evlist: 156 evlist__delete(evlist); 157 return ret; 158 } 159