[IPVS] retry to run kernel_thread when memory is temporarily exhausted

net/ipv4/ipvs/ip_vs_sync.c

@@ -618,8 +618,6 @@ ip_vs_receive(struct socket *sock, char *buffer, const size_t buflen)
 }
 
 
-static int errno;
-
 static DECLARE_WAIT_QUEUE_HEAD(sync_wait);
 static pid_t sync_master_pid = 0;
 static pid_t sync_backup_pid = 0;
@@ -766,10 +764,10 @@ static int sync_thread(void *startup)
 
 	if (ip_vs_sync_state & IP_VS_STATE_MASTER && !sync_master_pid) {
 		state = IP_VS_STATE_MASTER;
-		name = "ipvs syncmaster";
+		name = "ipvs_syncmaster";
 	} else if (ip_vs_sync_state & IP_VS_STATE_BACKUP && !sync_backup_pid) {
 		state = IP_VS_STATE_BACKUP;
-		name = "ipvs syncbackup";
+		name = "ipvs_syncbackup";
 	} else {
 		IP_VS_BUG();
 		ip_vs_use_count_dec();
@@ -827,10 +825,19 @@ static int sync_thread(void *startup)
 
 static int fork_sync_thread(void *startup)
 {
+	pid_t pid;
+
 	/* fork the sync thread here, then the parent process of the
 	   sync thread is the init process after this thread exits. */
-	if (kernel_thread(sync_thread, startup, 0) < 0)
-		IP_VS_BUG();
+  repeat:
+	if ((pid = kernel_thread(sync_thread, startup, 0)) < 0) {
+		IP_VS_ERR("could not create sync_thread due to %d... "
+			  "retrying.\n", pid);
+		current->state = TASK_UNINTERRUPTIBLE;
+		schedule_timeout(HZ);
+		goto repeat;
+	}
+
 	return 0;
 }
 
@@ -857,8 +864,14 @@ int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
 		ip_vs_backup_syncid = syncid;
 	}
 
-	if ((pid = kernel_thread(fork_sync_thread, &startup, 0)) < 0)
-		IP_VS_BUG();
+  repeat:
+	if ((pid = kernel_thread(fork_sync_thread, &startup, 0)) < 0) {
+		IP_VS_ERR("could not create fork_sync_thread due to %d... "
+			  "retrying.\n", pid);
+		current->state = TASK_UNINTERRUPTIBLE;
+		schedule_timeout(HZ);
+		goto repeat;
+	}
 
 	wait_for_completion(&startup);