diff --git a/ChangeLog b/ChangeLog
index 0159aab3d..a6d62da6c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-01-06  Colin Watson  <cjwatson@ubuntu.com>
+
+	* grub-core/kern/emu/getroot.c (find_root_device_from_mountinfo):
+	Fix prefix check to handle the case where dir ends with a slash
+	(most significantly, "/" itself).
+	Reported by: Michael Vogt.
+
 2011-01-05  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Run terminfo_cls on initing terminfo output to clear the screen and
diff --git a/grub-core/kern/emu/getroot.c b/grub-core/kern/emu/getroot.c
index 5356685e9..aedef9e0e 100644
--- a/grub-core/kern/emu/getroot.c
+++ b/grub-core/kern/emu/getroot.c
@@ -135,8 +135,12 @@ find_root_device_from_mountinfo (const char *dir)
 	continue; /* only a subtree is mounted */
 
       enc_path_len = strlen (enc_path);
+      /* Check that enc_path is a prefix of dir.  The prefix must either be
+         the entire string, or end with a slash, or be immediately followed
+         by a slash.  */
       if (strncmp (dir, enc_path, enc_path_len) != 0 ||
-	  (dir[enc_path_len] && dir[enc_path_len] != '/'))
+	  (enc_path_len && dir[enc_path_len - 1] != '/' &&
+	   dir[enc_path_len] && dir[enc_path_len] != '/'))
 	continue;
 
       /* This is a parent of the requested directory.  /proc/self/mountinfo