--- linux-2.4.18-orig/drivers/md/md.c	Wed Oct  2 11:59:00 2002
+++ linux-2.4.18/drivers/md/md.c	Wed Oct  2 11:58:38 2002
@@ -395,6 +395,16 @@
 
 static unsigned int calc_sb_csum(mdp_super_t * sb);
  
+/*
+ * validate_sb
+ * This checks for obvious inconsistencies that may have occurred 
+ * with values in the raid superblock.  Further work needs to be 
+ * done to find the root cause of each of these, but this at least
+ * keeps the superblock sane, so the system will boot.
+ * Currently this is called as a safeguard before a write of the sb.
+ * Along with any future work, the mddev->private values (e.g. raid1) 
+ * need to stay sync'd up with the superblock.     -- Andy Cress
+ */
 int validate_sb(mdp_super_t *sb, int op)
 {
    int changed = 0;
@@ -956,6 +966,10 @@
 		MD_BUG();
 		return 1;
 	}
+	if (!rdev->dev) {
+		MD_BUG();
+		return 1;
+	}
 
 	dev = rdev->dev;
 	sb_offset = calc_dev_sboffset(dev, rdev->mddev, 1);
@@ -1048,6 +1062,7 @@
 	int err, count = 100;
 	struct md_list_head *tmp;
 	mdk_rdev_t *rdev;
+	int i;
 
 	if (!mddev->sb_dirty) {
 		printk("hm, md_update_sb() called without ->sb_dirty == 1, from %p.\n", __builtin_return_address(0));
@@ -1055,6 +1070,10 @@
 	}
 	mddev->sb_dirty = 0;
 repeat:
+	if (!mddev->sb) {
+		MD_BUG();
+		return 1;
+	}
 	mddev->sb->utime = CURRENT_TIME;
 	if ((++mddev->sb->events_lo)==0)
 		++mddev->sb->events_hi;
@@ -1082,6 +1101,7 @@
 					mdidx(mddev));
 
 	err = 0;
+	i = 0;
 	ITERATE_RDEV(mddev,rdev,tmp) {
 		printk(KERN_INFO "md: ");
 		if (rdev->faulty)
@@ -1090,12 +1110,18 @@
 			printk("(skipping alias ");
 
 		printk("%s ", partition_name(rdev->dev));
-		if (!rdev->faulty && !rdev->alias_device) {
+		/* check for rdev->sb NULL here also.  ARC*/
+		if (!rdev->faulty && !rdev->alias_device && rdev->sb) {
 			printk("[events: %08lx]",
 				(unsigned long)rdev->sb->events_lo);
 			err += write_disk_sb(rdev);
 		} else
 			printk(")\n");
+		if (i >= mddev->nb_dev) {  /* ARC*/
+			printk("md_update_sb: iterate_rdev limit reached\n");
+			break;
+			}
+		i++;
 	}
 	if (err) {
 		if (--count) {
@@ -3847,7 +3873,7 @@
 		printk(KERN_WARNING "md: md=%d, Minor device number too high.\n", minor);
 		return 0;
 	} else if (md_setup_args.device_names[minor]) {
-		printk(KERN_WARNING "md: md=%d, Specified more then once. "
+		printk(KERN_WARNING "md: md=%d, Specified more than once. "
 		       "Replacing previous definition.\n", minor);
 	}
 	switch (get_option(&str, &level)) {	/* RAID Personality */