Merge 6.2 RC36.2-rc3

1 files changed, 227 insertions, 65 deletions

diff --git a/src/server.c b/src/server.c
index 0551eb3e4..faaca7215 100644
--- a/src/server.c
+++ b/src/server.c
@@ -201,6 +201,14 @@ struct redisCommand redisCommandTable[] = {
      "read-only fast @string",
      0,NULL,1,1,1,0,0,0},
 
+    {"getex",getexCommand,-2,
+     "write fast @string",
+     0,NULL,1,1,1,0,0,0},
+
+    {"getdel",getdelCommand,2,
+     "write fast @string",
+     0,NULL,1,1,1,0,0,0},
+
     /* Note that we can't flag set as fast, since it may perform an
      * implicit DEL of a large key. */
     {"set",setCommand,-3,
@@ -449,15 +457,15 @@ struct redisCommand redisCommandTable[] = {
 
     {"zunionstore",zunionstoreCommand,-4,
      "write use-memory @sortedset",
-     0,zunionInterDiffStoreGetKeys,0,0,0,0,0,0},
+     0,zunionInterDiffStoreGetKeys,1,1,1,0,0,0},
 
     {"zinterstore",zinterstoreCommand,-4,
      "write use-memory @sortedset",
-     0,zunionInterDiffStoreGetKeys,0,0,0,0,0,0},
+     0,zunionInterDiffStoreGetKeys,1,1,1,0,0,0},
 
     {"zdiffstore",zdiffstoreCommand,-4,
      "write use-memory @sortedset",
-     0,zunionInterDiffStoreGetKeys,0,0,0,0,0,0},
+     0,zunionInterDiffStoreGetKeys,1,1,1,0,0,0},
 
     {"zunion",zunionCommand,-3,
      "read-only @sortedset",
@@ -547,6 +555,10 @@ struct redisCommand redisCommandTable[] = {
      "write no-script fast @sortedset @blocking",
      0,NULL,1,-2,1,0,0,0},
 
+    {"zrandmember",zrandmemberCommand,-2,
+     "read-only random @sortedset",
+     0,NULL,1,1,1,0,0,0},
+
     {"hset",hsetCommand,-4,
      "write use-memory fast @hash",
      0,NULL,1,1,1,0,0,0},
@@ -603,6 +615,10 @@ struct redisCommand redisCommandTable[] = {
      "read-only fast @hash",
      0,NULL,1,1,1,0,0,0},
 
+    {"hrandfield",hrandfieldCommand,-2,
+     "read-only random @hash",
+     0,NULL,1,1,1,0,0,0},
+
     {"hscan",hscanCommand,-3,
      "read-only random @hash",
      0,NULL,1,1,1,0,0,0},
@@ -744,7 +760,7 @@ struct redisCommand redisCommandTable[] = {
      "admin no-script",
      0,NULL,0,0,0,0,0,0},
 
-    {"psync",syncCommand,3,
+    {"psync",syncCommand,-3,
      "admin no-script",
      0,NULL,0,0,0,0,0,0},
 
@@ -941,7 +957,7 @@ struct redisCommand redisCommandTable[] = {
 
     {"georadius_ro",georadiusroCommand,-6,
      "read-only @geo",
-     0,georadiusGetKeys,1,1,1,0,0,0},
+     0,NULL,1,1,1,0,0,0},
 
     {"georadiusbymember",georadiusbymemberCommand,-5,
      "write use-memory @geo",
@@ -949,7 +965,7 @@ struct redisCommand redisCommandTable[] = {
 
     {"georadiusbymember_ro",georadiusbymemberroCommand,-5,
      "read-only @geo",
-     0,georadiusGetKeys,1,1,1,0,0,0},
+     0,NULL,1,1,1,0,0,0},
 
     {"geohash",geohashCommand,-2,
      "read-only @geo",
@@ -1016,11 +1032,11 @@ struct redisCommand redisCommandTable[] = {
 
     {"xread",xreadCommand,-4,
      "read-only @stream @blocking",
-     0,xreadGetKeys,1,1,1,0,0,0},
+     0,xreadGetKeys,0,0,0,0,0,0},
 
     {"xreadgroup",xreadCommand,-7,
      "write @stream @blocking",
-     0,xreadGetKeys,1,1,1,0,0,0},
+     0,xreadGetKeys,0,0,0,0,0,0},
 
     {"xgroup",xgroupCommand,-2,
      "write use-memory @stream",
@@ -1084,6 +1100,10 @@ struct redisCommand redisCommandTable[] = {
 
     {"reset",resetCommand,1,
      "no-script ok-stale ok-loading fast @connection",
+     0,NULL,0,0,0,0,0,0},
+
+    {"failover",failoverCommand,-1,
+     "admin no-script ok-stale",
      0,NULL,0,0,0,0,0,0}
 };
 
@@ -1444,6 +1464,17 @@ dictType hashDictType = {
     NULL                        /* allow to expand */
 };
 
+/* Dict type without destructor */
+dictType sdsReplyDictType = {
+    dictSdsHash,                /* hash function */
+    NULL,                       /* key dup */
+    NULL,                       /* val dup */
+    dictSdsKeyCompare,          /* key compare */
+    NULL,                       /* key destructor */
+    NULL,                       /* val destructor */
+    NULL                        /* allow to expand */
+};
+
 /* Keylist hash table type has unencoded redis objects as keys and
  * lists as values. It's used for blocking operations (BLPOP) and to
  * map swapped keys to a list of clients waiting for this keys to be loaded. */
@@ -1592,6 +1623,9 @@ void resetChildState() {
     server.stat_current_cow_bytes = 0;
     updateDictResizePolicy();
     closeChildInfoPipe();
+    moduleFireServerEvent(REDISMODULE_EVENT_FORK_CHILD,
+                          REDISMODULE_SUBEVENT_FORK_CHILD_DIED,
+                          NULL);
 }
 
 /* Return if child type is mutual exclusive with other fork children */
@@ -2159,14 +2193,15 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
 
     /* AOF postponed flush: Try at every cron cycle if the slow fsync
      * completed. */
-    if (server.aof_flush_postponed_start) flushAppendOnlyFile(0);
+    if (server.aof_state == AOF_ON && server.aof_flush_postponed_start)
+        flushAppendOnlyFile(0);
 
     /* AOF write errors: in this case we have a buffer to flush as well and
      * clear the AOF error in case of success to make the DB writable again,
      * however to try every second is enough in case of 'hz' is set to
      * a higher frequency. */
     run_with_period(1000) {
-        if (server.aof_last_write_status == C_ERR)
+        if (server.aof_state == AOF_ON && server.aof_last_write_status == C_ERR)
             flushAppendOnlyFile(0);
     }
 
@@ -2174,8 +2209,15 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
     checkClientPauseTimeoutAndReturnIfPaused();
 
     /* Replication cron function -- used to reconnect to master,
-     * detect transfer failures, start background RDB transfers and so forth. */
-    run_with_period(1000) replicationCron();
+     * detect transfer failures, start background RDB transfers and so forth. 
+     * 
+     * If Redis is trying to failover then run the replication cron faster so
+     * progress on the handshake happens more quickly. */
+    if (server.failover_state != NO_FAILOVER) {
+        run_with_period(100) replicationCron();
+    } else {
+        run_with_period(1000) replicationCron();
+    }
 
     /* Run the Redis Cluster cron. */
     run_with_period(100) {
@@ -2386,12 +2428,18 @@ void beforeSleep(struct aeEventLoop *eventLoop) {
         server.get_ack_from_slaves = 0;
     }
 
+    /* We may have recieved updates from clients about their current offset. NOTE:
+     * this can't be done where the ACK is recieved since failover will disconnect 
+     * our clients. */
+    updateFailoverStatus();
+
     /* Send the invalidation messages to clients participating to the
      * client side caching protocol in broadcasting (BCAST) mode. */
     trackingBroadcastInvalidationMessages();
 
     /* Write the AOF buffer on disk */
-    flushAppendOnlyFile(0);
+    if (server.aof_state == AOF_ON)
+        flushAppendOnlyFile(0);
 
     /* Handle writes with pending output buffers. */
     handleClientsWithPendingWritesUsingThreads();
@@ -2532,6 +2580,12 @@ void createSharedObjects(void) {
     /* Used in the LMOVE/BLMOVE commands */
     shared.left = createStringObject("left",4);
     shared.right = createStringObject("right",5);
+    shared.pexpireat = createStringObject("PEXPIREAT",9);
+    shared.pexpire = createStringObject("PEXPIRE",7);
+    shared.persist = createStringObject("PERSIST",7);
+    shared.set = createStringObject("SET",3);
+    shared.pxat = createStringObject("PXAT", 4);
+    shared.px = createStringObject("PX",2);
     for (j = 0; j < OBJ_SHARED_INTEGERS; j++) {
         shared.integers[j] =
             makeObjectShared(createObject(OBJ_STRING,(void*)(long)j));
@@ -2634,6 +2688,13 @@ void initServerConfig(void) {
     server.repl_backlog_off = 0;
     server.repl_no_slaves_since = time(NULL);
 
+    /* Failover related */
+    server.failover_end_time = 0;
+    server.force_failover = 0;
+    server.target_replica_host = NULL;
+    server.target_replica_port = 0;
+    server.failover_state = NO_FAILOVER;
+
     /* Client output buffer limits */
     for (j = 0; j < CLIENT_TYPE_OBUF_COUNT; j++)
         server.client_obuf_limits[j] = clientBufferLimitsDefaults[j];
@@ -2957,6 +3018,7 @@ int listenToPort(int port, int *fds, int *count) {
             return C_ERR;
         }
         anetNonBlock(NULL,fds[*count]);
+        anetCloexec(fds[*count]);
         (*count)++;
     }
     return C_OK;
@@ -3095,6 +3157,7 @@ void initServer(void) {
             exit(1);
         }
         anetNonBlock(NULL,server.sofd);
+        anetCloexec(server.sofd);
     }
 
     /* Abort if there are no listening sockets at all. */
@@ -3557,7 +3620,7 @@ void preventCommandReplication(client *c) {
  */
 void call(client *c, int flags) {
     long long dirty;
-    ustime_t start, duration;
+    monotime call_timer;
     int client_old_flags = c->flags;
     struct redisCommand *real_cmd = c->cmd;
     static long long prev_err_count;
@@ -3583,9 +3646,10 @@ void call(client *c, int flags) {
     dirty = server.dirty;
     prev_err_count = server.stat_total_error_replies;
     updateCachedTime(0);
-    start = server.ustime;
+    elapsedStart(&call_timer);
     c->cmd->proc(c);
-    duration = ustime()-start;
+    const long duration = elapsedUs(call_timer);
+    c->duration = duration;
     dirty = server.dirty-dirty;
     if (dirty < 0) dirty = 0;
 
@@ -3629,7 +3693,10 @@ void call(client *c, int flags) {
          * arguments. */
         robj **argv = c->original_argv ? c->original_argv : c->argv;
         int argc = c->original_argv ? c->original_argc : c->argc;
-        slowlogPushEntryIfNeeded(c,argv,argc,duration);
+        /* If the client is blocked we will handle slowlog when it is unblocked . */
+        if (!(c->flags & CLIENT_BLOCKED)) {
+            slowlogPushEntryIfNeeded(c,argv,argc,duration);
+        }
     }
     freeClientOriginalArgv(c);
 
@@ -4682,7 +4749,7 @@ sds genRedisInfoString(const char *section) {
             "aof_last_cow_size:%zu\r\n"
             "module_fork_in_progress:%d\r\n"
             "module_fork_last_cow_size:%zu\r\n",
-            server.loading,
+            (int)server.loading,
             server.stat_current_cow_bytes,
             server.dirty,
             server.child_type == CHILD_TYPE_RDB,
@@ -4972,6 +5039,7 @@ sds genRedisInfoString(const char *section) {
             }
         }
         info = sdscatprintf(info,
+            "master_failover_state:%s\r\n"
             "master_replid:%s\r\n"
             "master_replid2:%s\r\n"
             "master_repl_offset:%lld\r\n"
@@ -4980,6 +5048,7 @@ sds genRedisInfoString(const char *section) {
             "repl_backlog_size:%lld\r\n"
             "repl_backlog_first_byte_offset:%lld\r\n"
             "repl_backlog_histlen:%lld\r\n",
+            getFailoverStateString(),
             server.replid,
             server.replid2,
             server.master_repl_offset,
@@ -5184,7 +5253,7 @@ static int smapsGetSharedDirty(unsigned long addr) {
     FILE *f;
 
     f = fopen("/proc/self/smaps", "r");
-    serverAssert(f);
+    if (!f) return -1;
 
     while (1) {
         if (!fgets(buf, sizeof(buf), f))
@@ -5195,8 +5264,8 @@ static int smapsGetSharedDirty(unsigned long addr) {
             in_mapping = from <= addr && addr < to;
 
         if (in_mapping && !memcmp(buf, "Shared_Dirty:", 13)) {
-            ret = sscanf(buf, "%*s %d", &val);
-            serverAssert(ret == 1);
+            sscanf(buf, "%*s %d", &val);
+            /* If parsing fails, we remain with val == -1 */
             break;
         }
     }
@@ -5210,23 +5279,33 @@ static int smapsGetSharedDirty(unsigned long addr) {
  * kernel is affected.
  * The bug was fixed in commit ff1712f953e27f0b0718762ec17d0adb15c9fd0b
  * titled: "arm64: pgtable: Ensure dirty bit is preserved across pte_wrprotect()"
- * Return 1 if the kernel seems to be affected, and 0 otherwise. */
+ * Return -1 on unexpected test failure, 1 if the kernel seems to be affected,
+ * and 0 otherwise. */
 int linuxMadvFreeForkBugCheck(void) {
-    int ret, pipefd[2];
+    int ret, pipefd[2] = { -1, -1 };
     pid_t pid;
-    char *p, *q, bug_found = 0;
-    const long map_size = 3 * 4096;
+    char *p = NULL, *q;
+    int bug_found = 0;
+    long page_size = sysconf(_SC_PAGESIZE);
+    long map_size = 3 * page_size;
 
     /* Create a memory map that's in our full control (not one used by the allocator). */
     p = mmap(NULL, map_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-    serverAssert(p != MAP_FAILED);
+    if (p == MAP_FAILED) {
+        serverLog(LL_WARNING, "Failed to mmap(): %s", strerror(errno));
+        return -1;
+    }
 
-    q = p + 4096;
+    q = p + page_size;
 
     /* Split the memory map in 3 pages by setting their protection as RO|RW|RO to prevent
      * Linux from merging this memory map with adjacent VMAs. */
-    ret = mprotect(q, 4096, PROT_READ | PROT_WRITE);
-    serverAssert(!ret);
+    ret = mprotect(q, page_size, PROT_READ | PROT_WRITE);
+    if (ret < 0) {
+        serverLog(LL_WARNING, "Failed to mprotect(): %s", strerror(errno));
+        bug_found = -1;
+        goto exit;
+    }
 
     /* Write to the page once to make it resident */
     *(volatile char*)q = 0;
@@ -5235,8 +5314,16 @@ int linuxMadvFreeForkBugCheck(void) {
 #ifndef MADV_FREE
 #define MADV_FREE 8
 #endif
-    ret = madvise(q, 4096, MADV_FREE);
-    serverAssert(!ret);
+    ret = madvise(q, page_size, MADV_FREE);
+    if (ret < 0) {
+        /* MADV_FREE is not available on older kernels that are presumably
+         * not affected. */
+        if (errno == EINVAL) goto exit;
+
+        serverLog(LL_WARNING, "Failed to madvise(): %s", strerror(errno));
+        bug_found = -1;
+        goto exit;
+    }
 
     /* Write to the page after being marked for freeing, this is supposed to take
      * ownership of that page again. */
@@ -5244,37 +5331,47 @@ int linuxMadvFreeForkBugCheck(void) {
 
     /* Create a pipe for the child to return the info to the parent. */
     ret = pipe(pipefd);
-    serverAssert(!ret);
+    if (ret < 0) {
+        serverLog(LL_WARNING, "Failed to create pipe: %s", strerror(errno));
+        bug_found = -1;
+        goto exit;
+    }
 
     /* Fork the process. */
     pid = fork();
-    serverAssert(pid >= 0);
-    if (!pid) {
-        /* Child: check if the page is marked as dirty, expecing 4 (kB).
+    if (pid < 0) {
+        serverLog(LL_WARNING, "Failed to fork: %s", strerror(errno));
+        bug_found = -1;
+        goto exit;
+    } else if (!pid) {
+        /* Child: check if the page is marked as dirty, page_size in kb.
          * A value of 0 means the kernel is affected by the bug. */
-        if (!smapsGetSharedDirty((unsigned long)q))
+        ret = smapsGetSharedDirty((unsigned long) q);
+        if (!ret)
             bug_found = 1;
+        else if (ret == -1)     /* Failed to read */
+            bug_found = -1;
 
-        ret = write(pipefd[1], &bug_found, 1);
-        serverAssert(ret == 1);
-
+        if (write(pipefd[1], &bug_found, sizeof(bug_found)) < 0)
+            serverLog(LL_WARNING, "Failed to write to parent: %s", strerror(errno));
         exit(0);
     } else {
         /* Read the result from the child. */
-        ret = read(pipefd[0], &bug_found, 1);
-        serverAssert(ret == 1);
+        ret = read(pipefd[0], &bug_found, sizeof(bug_found));
+        if (ret < 0) {
+            serverLog(LL_WARNING, "Failed to read from child: %s", strerror(errno));
+            bug_found = -1;
+        }
 
         /* Reap the child pid. */
-        serverAssert(waitpid(pid, NULL, 0) == pid);
+        waitpid(pid, NULL, 0);
     }
 
+exit:
     /* Cleanup */
-    ret = close(pipefd[0]);
-    serverAssert(!ret);
-    ret = close(pipefd[1]);
-    serverAssert(!ret);
-    ret = munmap(p, map_size);
-    serverAssert(!ret);
+    if (pipefd[0] != -1) close(pipefd[0]);
+    if (pipefd[1] != -1) close(pipefd[1]);
+    if (p != NULL) munmap(p, map_size);
 
     return bug_found;
 }
@@ -5470,7 +5567,7 @@ void setupChildSignalHandlers(void) {
  * of the parent process, e.g. fd(socket or flock) etc.
  * should close the resources not used by the child process, so that if the
  * parent restarts it can bind/lock despite the child possibly still running. */
-void closeClildUnusedResourceAfterFork() {
+void closeChildUnusedResourceAfterFork() {
     closeListeningSockets(0);
     if (server.cluster_enabled && server.cluster_config_file_lock_fd != -1)
         close(server.cluster_config_file_lock_fd);  /* don't care if this fails */
@@ -5497,7 +5594,7 @@ int redisFork(int purpose) {
         server.in_fork_child = purpose;
         setOOMScoreAdj(CONFIG_OOM_BGCHILD);
         setupChildSignalHandlers();
-        closeClildUnusedResourceAfterFork();
+        closeChildUnusedResourceAfterFork();
     } else {
         /* Parent */
         server.stat_total_forks++;
@@ -5523,6 +5620,9 @@ int redisFork(int purpose) {
         }
 
         updateDictResizePolicy();
+        moduleFireServerEvent(REDISMODULE_EVENT_FORK_CHILD,
+                              REDISMODULE_SUBEVENT_FORK_CHILD_BORN,
+                              NULL);
     }
     return childpid;
 }
@@ -5533,7 +5633,7 @@ void sendChildCOWInfo(int ptype, int on_exit, char *pname) {
     if (private_dirty) {
         serverLog(on_exit ? LL_NOTICE : LL_VERBOSE,
             "%s: %zu MB of memory used by copy-on-write",
-            pname, private_dirty);
+            pname, private_dirty/(1024*1024));
     }
 
     sendChildInfo(ptype, on_exit, private_dirty);
@@ -5598,20 +5698,68 @@ void redisOutOfMemoryHandler(size_t allocation_size) {
         allocation_size);
 }
 
-void redisSetProcTitle(char *title) {
+/* Callback for sdstemplate on proc-title-template. See redis.conf for
+ * supported variables.
+ */
+static sds redisProcTitleGetVariable(const sds varname, void *arg)
+{
+    if (!strcmp(varname, "title")) {
+        return sdsnew(arg);
+    } else if (!strcmp(varname, "listen-addr")) {
+        if (server.port || server.tls_port)
+            return sdscatprintf(sdsempty(), "%s:%u",
+                                server.bindaddr_count ? server.bindaddr[0] : "*",
+                                server.port ? server.port : server.tls_port);
+        else
+            return sdscatprintf(sdsempty(), "unixsocket:%s", server.unixsocket);
+    } else if (!strcmp(varname, "server-mode")) {
+        if (server.cluster_enabled) return sdsnew("[cluster]");
+        else if (server.sentinel_mode) return sdsnew("[sentinel]");
+        else return sdsempty();
+    } else if (!strcmp(varname, "config-file")) {
+        return sdsnew(server.configfile ? server.configfile : "-");
+    } else if (!strcmp(varname, "port")) {
+        return sdscatprintf(sdsempty(), "%u", server.port);
+    } else if (!strcmp(varname, "tls-port")) {
+        return sdscatprintf(sdsempty(), "%u", server.tls_port);
+    } else if (!strcmp(varname, "unixsocket")) {
+        return sdsnew(server.unixsocket);
+    } else
+        return NULL;    /* Unknown variable name */
+}
+
+/* Expand the specified proc-title-template string and return a newly
+ * allocated sds, or NULL. */
+static sds expandProcTitleTemplate(const char *template, const char *title) {
+    sds res = sdstemplate(template, redisProcTitleGetVariable, (void *) title);
+    if (!res)
+        return NULL;
+    return sdstrim(res, " ");
+}
+/* Validate the specified template, returns 1 if valid or 0 otherwise. */
+int validateProcTitleTemplate(const char *template) {
+    int ok = 1;
+    sds res = expandProcTitleTemplate(template, "");
+    if (!res)
+        return 0;
+    if (sdslen(res) == 0) ok = 0;
+    sdsfree(res);
+    return ok;
+}
+
+int redisSetProcTitle(char *title) {
 #ifdef USE_SETPROCTITLE
-    char *server_mode = "";
-    if (server.cluster_enabled) server_mode = " [cluster]";
-    else if (server.sentinel_mode) server_mode = " [sentinel]";
-
-    setproctitle("%s %s:%d%s",
-        title,
-        server.bindaddr_count ? server.bindaddr[0] : "*",
-        server.port ? server.port : server.tls_port,
-        server_mode);
+    if (!title) title = server.exec_argv[0];
+    sds proc_title = expandProcTitleTemplate(server.proc_title_template, title);
+    if (!proc_title) return C_ERR;  /* Not likely, proc_title_template is validated */
+
+    setproctitle("%s", proc_title);
+    sdsfree(proc_title);
 #else
     UNUSED(title);
 #endif
+
+    return C_OK;
 }
 
 void redisSetCpuAffinity(const char *cpulist) {
@@ -5751,6 +5899,12 @@ int main(int argc, char **argv) {
     init_genrand64(((long long) tv.tv_sec * 1000000 + tv.tv_usec) ^ getpid());
     crc64_init();
 
+    /* Store umask value. Because umask(2) only offers a set-and-get API we have
+     * to reset it and restore it back. We do this early to avoid a potential
+     * race condition with threads that could be creating files or directories.
+     */
+    umask(server.umask = umask(0777));
+
     uint8_t hashseed[16];
     getRandomBytes(hashseed,sizeof(hashseed));
     dictSetHashFunctionSeed(hashseed);
@@ -5843,6 +5997,7 @@ int main(int argc, char **argv) {
             exit(1);
         }
         loadServerConfig(server.configfile, config_from_stdin, options);
+        if (server.sentinel_mode) loadSentinelConfigFromQueue();
         sdsfree(options);
     }
 
@@ -5868,7 +6023,7 @@ int main(int argc, char **argv) {
     readOOMScoreAdj();
     initServer();
     if (background || server.pidfile) createPidFile();
-    redisSetProcTitle(argv[0]);
+    if (server.set_proc_title) redisSetProcTitle(NULL);
     redisAsciiArt();
     checkTcpBacklogSettings();
 
@@ -5878,10 +6033,17 @@ int main(int argc, char **argv) {
     #ifdef __linux__
         linuxMemoryWarnings();
     #if defined (__arm64__)
-        if (linuxMadvFreeForkBugCheck()) {
-            serverLog(LL_WARNING,"WARNING Your kernel has a bug that could lead to data corruption during background save. Please upgrade to the latest stable kernel.");
+        int ret;
+        if ((ret = linuxMadvFreeForkBugCheck())) {
+            if (ret == 1)
+                serverLog(LL_WARNING,"WARNING Your kernel has a bug that could lead to data corruption during background save. "
+                                     "Please upgrade to the latest stable kernel.");
+            else
+                serverLog(LL_WARNING, "Failed to test the kernel for a bug that could lead to data corruption during background save. "
+                                      "Your system could be affected, please report this error.");
             if (!checkIgnoreWarning("ARM64-COW-BUG")) {
-                serverLog(LL_WARNING,"Redis will now exit to prevent data corruption. Note that it is possible to suppress this warning by setting the following config: ignore-warnings ARM64-COW-BUG");
+                serverLog(LL_WARNING,"Redis will now exit to prevent data corruption. "
+                                     "Note that it is possible to suppress this warning by setting the following config: ignore-warnings ARM64-COW-BUG");
                 exit(1);
             }
         }