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void *bioProcessBackgroundJobs(void *arg) {
    ...
    ...
    pthread_mutex_lock(&bio_mutex[type]);
    ...
    ...

    while(1) {
        listNode *ln;

        /* The loop always starts with the lock hold. */
        if (listLength(bio_jobs[type]) == 0) {
            pthread_cond_wait(&bio_newjob_cond[type],&bio_mutex[type]);
            continue;
        }
        /* Pop the job from the queue. */
        ln = listFirst(bio_jobs[type]);
        job = ln->value;
        /* It is now possible to unlock the background system as we know have
         * a stand alone job structure to process.*/
        pthread_mutex_unlock(&bio_mutex[type]);

        /* Process the job accordingly to its type. */
        if (type == BIO_CLOSE_FILE) {
            close((long)job->arg1);
        } else if (type == BIO_AOF_FSYNC) {
            redis_fsync((long)job->arg1);
        } else if (type == BIO_LAZY_FREE) {
            /* What we free changes depending on what arguments are set:
             * arg1 -> free the object at pointer.
             * arg2 & arg3 -> free two dictionaries (a Redis DB).
             * only arg3 -> free the skiplist. */
            if (job->arg1)
                lazyfreeFreeObjectFromBioThread(job->arg1);
            else if (job->arg2 && job->arg3)
                lazyfreeFreeDatabaseFromBioThread(job->arg2,job->arg3);
            else if (job->arg3)
                lazyfreeFreeSlotsMapFromBioThread(job->arg3);
        } else {
            serverPanic("Wrong job type in bioProcessBackgroundJobs().");
        }
        ...

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void *bioProcessBackgroundJobs(void *arg) {
    ...
    ...
    pthread_mutex_lock(&bio_mutex[type]);
    ...
    ...

    while(1) {
        listNode *ln;

        /* The loop always starts with the lock hold. */
        if (listLength(bio_jobs[type]) == 0) {
            pthread_cond_wait(&bio_newjob_cond[type],&bio_mutex[type]);
            continue;
        }
        /* Pop the job from the queue. */
        ln = listFirst(bio_jobs[type]);
        job = ln->value;
        /* It is now possible to unlock the background system as we know have
         * a stand alone job structure to process.*/
        pthread_mutex_unlock(&bio_mutex[type]);

        /* Process the job accordingly to its type. */
        if (type == BIO_CLOSE_FILE) {
            close((long)job->arg1);
        } else if (type == BIO_AOF_FSYNC) {
            redis_fsync((long)job->arg1);
            asset(false);               // 강제로 오류 발생시킴.
        } else if (type == BIO_LAZY_FREE) {
        ...

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void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
...

#if defined(HAVE_PROC_MAPS)
    /* Test memory */
    serverLogRaw(LL_WARNING|LL_RAW, "\n------ FAST MEMORY TEST ------\n");
    bioKillThreads();
    if (memtest_test_linux_anonymous_maps()) {
        serverLogRaw(LL_WARNING|LL_RAW,
            "!!! MEMORY ERROR DETECTED! Check your memory ASAP !!!\n");
    } else {
        serverLogRaw(LL_WARNING|LL_RAW,
            "Fast memory test PASSED, however your memory can still be broken. Please run a memory test for several hours if possible.\n");
    }
#endif
...

    serverLogRaw(LL_WARNING|LL_RAW,
"\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
"       Please report the crash by opening an issue on github:\n\n"
"           http://github.com/antirez/redis/issues\n\n"
"  Suspect RAM error? Use redis-server --test-memory to verify it.\n\n"
);

    /* free(messages); Don't call free() with possibly corrupted memory. */
    if (server.daemonize && server.supervised == 0) unlink(server.pidfile);

    /* Make sure we exit with the right signal at the end. So for instance
     * the core will be dumped if enabled. */
    sigemptyset (&act.sa_mask);
    act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
    act.sa_handler = SIG_DFL;
    sigaction (sig, &act, NULL);
    kill(getpid(),sig);
}

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/* Kill the running bio threads in an unclean way. This function should be
 * used only when it's critical to stop the threads for some reason.
 * Currently Redis does this only on crash (for instance on SIGSEGV) in order
 * to perform a fast memory check without other threads messing with memory. */
void bioKillThreads(void) {
    int err, j;

    for (j = 0; j < BIO_NUM_OPS; j++) {
        if (bio_threads[j] && pthread_cancel(bio_threads[j]) == 0) {
            if ((err = pthread_join(bio_threads[j],NULL)) != 0) {
                serverLog(LL_WARNING,
                    "Bio thread for job type #%d can be joined: %s",
                        j, strerror(err));
            } else {
                serverLog(LL_WARNING,
                    "Bio thread for job type #%d terminated",j);
            }
        }
    }
}

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/* Kill the running bio threads in an unclean way. This function should be
 * used only when it's critical to stop the threads for some reason.
 * Currently Redis does this only on crash (for instance on SIGSEGV) in order
 * to perform a fast memory check without other threads messing with memory. */
void bioKillThreads(void) {
    int err, j;

    uint64_t tid = pthread_self();
    for (j = 0; j < REDIS_BIO_NUM_OPS; j++) {
        if (bio_threads[j] && tid != bio_threads[j] && pthread_cancel(bio_threads[j]) == 0) {
            if ((err = pthread_join(bio_threads[j],NULL)) != 0) {
                redisLog(REDIS_WARNING,
                    "Bio thread for job type #%d can be joined: %s",
                        j, strerror(err));
            } else {
                redisLog(REDIS_WARNING,
                    "Bio thread for job type #%d terminated",j);
            }
        }
    }
}