diff --git a/[refs] b/[refs]
index 4af5926069ec..1c8487aec44e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bf52c6f7af55c48ab0fd5f990460b884b428d906
+refs/heads/master: 8762202dd0d6e46854f786bdb6fb3780a1625efe
diff --git a/trunk/fs/jbd/journal.c b/trunk/fs/jbd/journal.c
index 9fe061fb8779..fea8dd661d2b 100644
--- a/trunk/fs/jbd/journal.c
+++ b/trunk/fs/jbd/journal.c
@@ -1135,6 +1135,14 @@ static int journal_get_superblock(journal_t *journal)
 		goto out;
 	}
 
+	if (be32_to_cpu(sb->s_first) == 0 ||
+	    be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
+		printk(KERN_WARNING
+			"JBD: Invalid start block of journal: %u\n",
+			be32_to_cpu(sb->s_first));
+		goto out;
+	}
+
 	return 0;
 
 out:
diff --git a/trunk/fs/jbd2/journal.c b/trunk/fs/jbd2/journal.c
index f24df13adc4e..d6e93d00833e 100644
--- a/trunk/fs/jbd2/journal.c
+++ b/trunk/fs/jbd2/journal.c
@@ -1251,6 +1251,14 @@ static int journal_get_superblock(journal_t *journal)
 		goto out;
 	}
 
+	if (be32_to_cpu(sb->s_first) == 0 ||
+	    be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
+		printk(KERN_WARNING
+			"JBD2: Invalid start block of journal: %u\n",
+			be32_to_cpu(sb->s_first));
+		goto out;
+	}
+
 	return 0;
 
 out: