genksyms: Fix segfault with invalid declarations

commit d920f7c6 upstream.

Do not try to recover too early and segfault when parsing invalid
declarations such as

echo 'int (int);' | scripts/genksyms/genksyms
echo 'int a, (int);' | scripts/genksyms/genksyms
echo 'extern void *__inline_memcpy((void *), (const void *), (__kernel_size_t));' | scripts/genksyms/genksyms

The last one was a real-life bug with
include/asm-generic/asm-prototypes.h on x86_64.
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Michal Marek <mmarek@suse.com>
[arnd: rebase to 4.4, regenerate parse.tab.{c,h}]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scripts/genksyms/parse.tab.h_shipped

-/* A Bison parser, made by GNU Bison 2.7.  */
+/* A Bison parser, made by GNU Bison 3.0.4.  */
 
 /* Bison interface for Yacc-like parsers in C
-   
-      Copyright (C) 1984, 1989-1990, 2000-2012 Free Software Foundation, Inc.
-   
+
+   Copyright (C) 1984, 1989-1990, 2000-2015 Free Software Foundation, Inc.
+
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
-   
+
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
-   
+
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
@@ -26,93 +26,80 @@
    special exception, which will cause the skeleton and the resulting
    Bison output files to be licensed under the GNU General Public
    License without this special exception.
-   
+
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
-#ifndef YY_YY_SCRIPTS_GENKSYMS_PARSE_TAB_H_SHIPPED_INCLUDED
-# define YY_YY_SCRIPTS_GENKSYMS_PARSE_TAB_H_SHIPPED_INCLUDED
-/* Enabling traces.  */
+#ifndef YY_YY_PARSE_TAB_H_INCLUDED
+# define YY_YY_PARSE_TAB_H_INCLUDED
+/* Debug traces.  */
 #ifndef YYDEBUG
-# define YYDEBUG 1
+# define YYDEBUG 0
 #endif
 #if YYDEBUG
 extern int yydebug;
 #endif
 
-/* Tokens.  */
+/* Token type.  */
 #ifndef YYTOKENTYPE
 # define YYTOKENTYPE
-   /* Put the tokens into the symbol table, so that GDB and other debuggers
-      know about them.  */
-   enum yytokentype {
-     ASM_KEYW = 258,
-     ATTRIBUTE_KEYW = 259,
-     AUTO_KEYW = 260,
-     BOOL_KEYW = 261,
-     CHAR_KEYW = 262,
-     CONST_KEYW = 263,
-     DOUBLE_KEYW = 264,
-     ENUM_KEYW = 265,
-     EXTERN_KEYW = 266,
-     EXTENSION_KEYW = 267,
-     FLOAT_KEYW = 268,
-     INLINE_KEYW = 269,
-     INT_KEYW = 270,
-     LONG_KEYW = 271,
-     REGISTER_KEYW = 272,
-     RESTRICT_KEYW = 273,
-     SHORT_KEYW = 274,
-     SIGNED_KEYW = 275,
-     STATIC_KEYW = 276,
-     STRUCT_KEYW = 277,
-     TYPEDEF_KEYW = 278,
-     UNION_KEYW = 279,
-     UNSIGNED_KEYW = 280,
-     VOID_KEYW = 281,
-     VOLATILE_KEYW = 282,
-     TYPEOF_KEYW = 283,
-     EXPORT_SYMBOL_KEYW = 284,
-     ASM_PHRASE = 285,
-     ATTRIBUTE_PHRASE = 286,
-     TYPEOF_PHRASE = 287,
-     BRACE_PHRASE = 288,
-     BRACKET_PHRASE = 289,
-     EXPRESSION_PHRASE = 290,
-     CHAR = 291,
-     DOTS = 292,
-     IDENT = 293,
-     INT = 294,
-     REAL = 295,
-     STRING = 296,
-     TYPE = 297,
-     OTHER = 298,
-     FILENAME = 299
-   };
+  enum yytokentype
+  {
+    ASM_KEYW = 258,
+    ATTRIBUTE_KEYW = 259,
+    AUTO_KEYW = 260,
+    BOOL_KEYW = 261,
+    CHAR_KEYW = 262,
+    CONST_KEYW = 263,
+    DOUBLE_KEYW = 264,
+    ENUM_KEYW = 265,
+    EXTERN_KEYW = 266,
+    EXTENSION_KEYW = 267,
+    FLOAT_KEYW = 268,
+    INLINE_KEYW = 269,
+    INT_KEYW = 270,
+    LONG_KEYW = 271,
+    REGISTER_KEYW = 272,
+    RESTRICT_KEYW = 273,
+    SHORT_KEYW = 274,
+    SIGNED_KEYW = 275,
+    STATIC_KEYW = 276,
+    STRUCT_KEYW = 277,
+    TYPEDEF_KEYW = 278,
+    UNION_KEYW = 279,
+    UNSIGNED_KEYW = 280,
+    VOID_KEYW = 281,
+    VOLATILE_KEYW = 282,
+    TYPEOF_KEYW = 283,
+    EXPORT_SYMBOL_KEYW = 284,
+    ASM_PHRASE = 285,
+    ATTRIBUTE_PHRASE = 286,
+    TYPEOF_PHRASE = 287,
+    BRACE_PHRASE = 288,
+    BRACKET_PHRASE = 289,
+    EXPRESSION_PHRASE = 290,
+    CHAR = 291,
+    DOTS = 292,
+    IDENT = 293,
+    INT = 294,
+    REAL = 295,
+    STRING = 296,
+    TYPE = 297,
+    OTHER = 298,
+    FILENAME = 299
+  };
 #endif
 
-
+/* Value type.  */
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 typedef int YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1
-# define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
 #endif
 
+
 extern YYSTYPE yylval;
 
-#ifdef YYPARSE_PARAM
-#if defined __STDC__ || defined __cplusplus
-int yyparse (void *YYPARSE_PARAM);
-#else
-int yyparse ();
-#endif
-#else /* ! YYPARSE_PARAM */
-#if defined __STDC__ || defined __cplusplus
 int yyparse (void);
-#else
-int yyparse ();
-#endif
-#endif /* ! YYPARSE_PARAM */
 
-#endif /* !YY_YY_SCRIPTS_GENKSYMS_PARSE_TAB_H_SHIPPED_INCLUDED  */
+#endif /* !YY_YY_PARSE_TAB_H_INCLUDED  */

scripts/genksyms/parse.y

@@ -320,8 +320,6 @@ direct_declarator:
 		{ $$ = $2; }
 	| '(' declarator ')'
 		{ $$ = $3; }
-	| '(' error ')'
-		{ $$ = $3; }
 	;
 
 /* Nested declarators differ from regular declarators in that they do