Bug#536354: linux-2.6: [s390,lenny] kernel panic during boot

[Frans Pop <elendil@planet.nl>]

tags 536354 patch
thanks

On Friday 10 July 2009, Frans Pop wrote:
> On Friday 10 July 2009, dann frazier wrote:
> > Maybe the -fwrapv change?
>
> Bingo. Makes a lot of sense too for an issue related to gcc version.

I've proposed the attached patch on lkml: http://lkml.org/lkml/2009/7/10/49.

From: Frans Pop <elendil@planet.nl>
Subject: Only add '-fwrapv' gcc CFLAGS for gcc 4.3 and later

This flag has been shown to cause init to segfault for kernels
compiled with gcc-4.1. gcc version 4.2.4 has been shown to be OK,
but as there is some uncertainty the flag is only added for 4.3
and later.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=13012.

Signed-off-by: Frans Pop <elendil@planet.nl>

diff --git a/Makefile b/Makefile
index 0aeec59..2f8756e 100644
--- a/Makefile
+++ b/Makefile
@@ -565,7 +565,8 @@ KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
 KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,)
 
 # disable invalid "can't wrap" optimizations for signed / pointers
-KBUILD_CFLAGS	+= $(call cc-option,-fwrapv)
+KBUILD_CFLAGS  += $(shell if [ $(call cc-version) -ge 0430 ]; then \
+		    echo $(call cc-option,-fwrapv); fi ;)
 
 # revert to pre-gcc-4.4 behaviour of .eh_frame
 KBUILD_CFLAGS	+= $(call cc-option,-fno-dwarf2-cfi-asm)