Messages in this thread Patch in this message |  | | From | Frans Pop <> | Subject | [PATCH,v2] Only add '-fwrapv' to gcc CFLAGS for gcc 4.2 and later | Date | Fri, 10 Jul 2009 22:05:47 +0200 |
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On Friday 10 July 2009, Frans Pop wrote: > The discussion on issue looks to have died, but it has bitten Debian > stable ("Lenny") [1] as it causes init to die on s390 after a kernel > update. > > Here's a possible patch. The exact gcc version to check for is still a > bit open I guess. For the s390 issue I've confirmed that 4.2.4 is OK, > but for safety and because of Andrew's comment above I've set the test > for 4.3 in the patch.
Here's an updated patch as I found the gcc version check was incorrect (0430 should have been 0403; sorry).
I've now changed the check to allow -fwrapv for gcc 4.2 as that has been shown to work and because of the consideration mentioned in my previous mail.
--- From: Frans Pop <elendil@planet.nl> Subject: Only add '-fwrapv' to gcc CFLAGS for gcc 4.2 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.
This fixes http://bugzilla.kernel.org/show_bug.cgi?id=13012.
Reported-by: Barry K. Nathan <barryn@pobox.com> Signed-off-by: Frans Pop <elendil@planet.nl>
diff --git a/Makefile b/Makefile index 0aeec59..2519fde 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 0402 ]; 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)
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