diff --git a/[refs] b/[refs]
index b59f815b338e..8f8f1c06a82c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4ad33411308596f2f918603509729922a1ec4411
+refs/heads/master: 55f6cb9d0b364e7e8cb65b51193f5e4743c44fde
diff --git a/trunk/arch/x86/kernel/cpu/mkcapflags.pl b/trunk/arch/x86/kernel/cpu/mkcapflags.pl
index dfea390e1608..0c5b54919c7b 100644
--- a/trunk/arch/x86/kernel/cpu/mkcapflags.pl
+++ b/trunk/arch/x86/kernel/cpu/mkcapflags.pl
@@ -11,22 +11,35 @@
 print OUT "#include <asm/cpufeature.h>\n\n";
 print OUT "const char * const x86_cap_flags[NCAPINTS*32] = {\n";
 
+%features = ();
+$err = 0;
+
 while (defined($line = <IN>)) {
 	if ($line =~ /^\s*\#\s*define\s+(X86_FEATURE_(\S+))\s+(.*)$/) {
 		$macro = $1;
-		$feature = $2;
+		$feature = "\L$2";
 		$tail = $3;
 		if ($tail =~ /\/\*\s*\"([^"]*)\".*\*\//) {
-			$feature = $1;
+			$feature = "\L$1";
 		}
 
-		if ($feature ne '') {
-			printf OUT "\t%-32s = \"%s\",\n",
-				"[$macro]", "\L$feature";
+		next if ($feature eq '');
+
+		if ($features{$feature}++) {
+			print STDERR "$in: duplicate feature name: $feature\n";
+			$err++;
 		}
+		printf OUT "\t%-32s = \"%s\",%s\n", "[$macro]", $feature;
 	}
 }
 print OUT "};\n";
 
 close(IN);
 close(OUT);
+
+if ($err) {
+	unlink($out);
+	exit(1);
+}
+
+exit(0);