task-exit.c

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// SPDX-License-Identifier: GPL-2.0
#include "evlist.h"
#include "evsel.h"
#include "thread_map.h"
#include "cpumap.h"
#include "tests.h"

#include <errno.h>
#include <signal.h>

static int exited;
static int nr_exit;

static void sig_handler(int sig __maybe_unused)
{
    exited = 1;
}

/*
 * perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
 * we asked by setting its exec_error to this handler.
 */
static void workload_exec_failed_signal(int signo __maybe_unused,
                    siginfo_t *info __maybe_unused,
                    void *ucontext __maybe_unused)
{
    exited  = 1;
    nr_exit = -1;
}

/*
 * This test will start a workload that does nothing then it checks
 * if the number of exit event reported by the kernel is 1 or not
 * in order to check the kernel returns correct number of event.
 */
int test__task_exit(struct test *test __maybe_unused, int subtest __maybe_unused)
{
    int err = -1;
    union perf_event *event;
    struct perf_evsel *evsel;
    struct perf_evlist *evlist;
    struct target target = {
        .uid        = UINT_MAX,
        .uses_mmap  = true,
    };
    const char *argv[] = { "true", NULL };
    char sbuf[STRERR_BUFSIZE];
    struct cpu_map *cpus;
    struct thread_map *threads;
    struct perf_mmap *md;

    signal(SIGCHLD, sig_handler);

    evlist = perf_evlist__new_default();
    if (evlist == NULL) {
        pr_debug("perf_evlist__new_default\n");
        return -1;
    }

    /*
     * Create maps of threads and cpus to monitor. In this case
     * we start with all threads and cpus (-1, -1) but then in
     * perf_evlist__prepare_workload we'll fill in the only thread
     * we're monitoring, the one forked there.
     */
    cpus = cpu_map__dummy_new();
    threads = thread_map__new_by_tid(-1);
    if (!cpus || !threads) {
        err = -ENOMEM;
        pr_debug("Not enough memory to create thread/cpu maps\n");
        goto out_free_maps;
    }

    perf_evlist__set_maps(evlist, cpus, threads);

    cpus    = NULL;
    threads = NULL;

    err = perf_evlist__prepare_workload(evlist, &target, argv, false,
                        workload_exec_failed_signal);
    if (err < 0) {
        pr_debug("Couldn't run the workload!\n");
        goto out_delete_evlist;
    }

    evsel = perf_evlist__first(evlist);
    evsel->attr.task = 1;
#ifdef __s390x__
    evsel->attr.sample_freq = 1000000;
#else
    evsel->attr.sample_freq = 1;
#endif
    evsel->attr.inherit = 0;
    evsel->attr.watermark = 0;
    evsel->attr.wakeup_events = 1;
    evsel->attr.exclude_kernel = 1;

    err = perf_evlist__open(evlist);
    if (err < 0) {
        pr_debug("Couldn't open the evlist: %s\n",
             str_error_r(-err, sbuf, sizeof(sbuf)));
        goto out_delete_evlist;
    }

    if (perf_evlist__mmap(evlist, 128) < 0) {
        pr_debug("failed to mmap events: %d (%s)\n", errno,
             str_error_r(errno, sbuf, sizeof(sbuf)));
        goto out_delete_evlist;
    }

    perf_evlist__start_workload(evlist);

retry:
    md = &evlist->mmap[0];
    if (perf_mmap__read_init(md) < 0)
        goto out_init;

    while ((event = perf_mmap__read_event(md)) != NULL) {
        if (event->header.type == PERF_RECORD_EXIT)
            nr_exit++;

        perf_mmap__consume(md);
    }
    perf_mmap__read_done(md);

out_init:
    if (!exited || !nr_exit) {
        perf_evlist__poll(evlist, -1);
        goto retry;
    }

    if (nr_exit != 1) {
        pr_debug("received %d EXIT records\n", nr_exit);
        err = -1;
    }

out_free_maps:
    cpu_map__put(cpus);
    thread_map__put(threads);
out_delete_evlist:
    perf_evlist__delete(evlist);
    return err;
}