[PATCH 4.9 75/83] lib/ubsan.c: dont mark __ubsan_handle_builtin_unreachable as noreturn

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@xxxxxxxx>

commit 1c23b4108d716cc848b38532063a8aca4f86add8 upstream.

gcc-8 complains about the prototype for this function:

  lib/ubsan.c:432:1: error: ignoring attribute 'noreturn' in declaration of a built-in function '__ubsan_handle_builtin_unreachable' because it conflicts with attribute 'const' [-Werror=attributes]

This is actually a GCC's bug. In GCC internals
__ubsan_handle_builtin_unreachable() declared with both 'noreturn' and
'const' attributes instead of only 'noreturn':

   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84210

Workaround this by removing the noreturn attribute.

[aryabinin: add information about GCC bug in changelog]
Link: http://lkml.kernel.org/r/20181107144516.4587-1-aryabinin@xxxxxxxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Acked-by: Olof Johansson <olof@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 lib/ubsan.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -451,8 +451,7 @@ void __ubsan_handle_shift_out_of_bounds(
 EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
 
 
-void __noreturn
-__ubsan_handle_builtin_unreachable(struct unreachable_data *data)
+void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
 {
 	unsigned long flags;