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authorLinus Torvalds <torvalds@linux-foundation.org>2009-07-12 11:25:04 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2009-07-19 20:38:56 -0700
commitd7de59fb74b6e9b94af8b9fcbfdf39eeae3b27be (patch)
parent0457e83ceec2a048a330713a3ae828c2fcd6c9f2 (diff)
Don't use '-fwrapv' compiler option: it's buggy in gcc-4.1.x
commit a137802ee839ace40079bebde24cfb416f73208a upstream. This causes kernel images that don't run init to completion with certain broken gcc versions. This fixes kernel bugzilla entry: http://bugzilla.kernel.org/show_bug.cgi?id=13012 I suspect the gcc problem is this: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28230 Fix the problem by using the -fno-strict-overflow flag instead, which not only does not exist in the known-to-be-broken versions of gcc (it was introduced later than fwrapv), but seems to be much less disturbing to gcc too: the difference in the generated code by -fno-strict-overflow are smaller (compared to using neither flag) than when using -fwrapv. Reported-by: Barry K. Nathan <barryn@pobox.com> Pushed-by: Frans Pop <elendil@planet.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1 files changed, 1 insertions, 1 deletions
diff --git a/Makefile b/Makefile
index 3aeb4c346184..e21190237587 100644
--- a/Makefile
+++ b/Makefile
@@ -574,7 +574,7 @@ 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 += $(call cc-option,-fno-strict-overflow)
# revert to pre-gcc-4.4 behaviour of .eh_frame
KBUILD_CFLAGS += $(call cc-option,-fno-dwarf2-cfi-asm)