[PATCH] Use before initialisation in devfs_mk_cdev()

As noted by Gergely Nagy:

  "devfs_mk_cdev() first checks the mode passed to it, and if it thinks
   it is not a char device, it prints a warning and aborts.  Now, this
   printing involves the local variable `buf' (char buf[64]), which is
   not initialised at that point."

The same problem also affects devfs_mk_bdev.

Fixed thus.

fs/devfs/base.c

@@ -1445,12 +1445,6 @@ int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
 	va_list args;
 	int error, n;
 
-	if (!S_ISBLK(mode)) {
-		printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
-				__FUNCTION__, mode, buf);
-		return -EINVAL;
-	}
-
 	va_start(args, fmt);
 	n = vsnprintf(buf, 64, fmt, args);
 	if (n >= 64 || !buf[0]) {
@@ -1458,6 +1452,12 @@ int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
 				__FUNCTION__);
 		return -EINVAL;
 	}
+	
+	if (!S_ISBLK(mode)) {
+		printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+				__FUNCTION__, mode, buf);
+		return -EINVAL;
+	}
 
 	de = _devfs_prepare_leaf(&dir, buf, mode);
 	if (!de) {
@@ -1491,12 +1491,6 @@ int devfs_mk_cdev(dev_t dev, umode_t mode, const char *fmt, ...)
 	va_list args;
 	int error, n;
 
-	if (!S_ISCHR(mode)) {
-		printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
-				__FUNCTION__, mode, buf);
-		return -EINVAL;
-	}
-
 	va_start(args, fmt);
 	n = vsnprintf(buf, 64, fmt, args);
 	if (n >= 64 || !buf[0]) {
@@ -1505,6 +1499,12 @@ int devfs_mk_cdev(dev_t dev, umode_t mode, const char *fmt, ...)
 		return -EINVAL;
 	}
 
+	if (!S_ISCHR(mode)) {
+		printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+				__FUNCTION__, mode, buf);
+		return -EINVAL;
+	}
+
 	de = _devfs_prepare_leaf(&dir, buf, mode);
 	if (!de) {
 		printk(KERN_WARNING "%s: could not prepare leaf for %s\n",