--- a/usr/src/uts/common/fs/dev/sdev_zvolops.c	Sat Jan 18 19:47:55 2014 +0000
+++ b/usr/src/uts/common/fs/dev/sdev_zvolops.c	Sun Dec 14 13:17:16 2014 +0000
@@ -792,7 +792,10 @@
 		return (devname_readdir_func(dvp, uiop, cred, eofp, 0));
 	}
 
-	ptr = strchr(ptr + 1, '/') + 1;
+	ptr = strchr(ptr + 1, '/');
+	if (ptr == NULL)
+		return (ENOENT);
+	ptr++;
 	rw_exit(&sdvp->sdev_contents);
 	sdev_iter_datasets(dvp, ZFS_IOC_DATASET_LIST_NEXT, ptr);
 	rw_enter(&sdvp->sdev_contents, RW_READER);