Subject: Re: linux-next: build warning after merge of the tip tree

From: "H. Peter Anvin" <[email-masked]>
Date: Fri, 18 Jul 2014 12:16:23 -0700

On 07/17/2014 10:00 PM, Stephen Rothwell wrote:
> Hi all,
> 
> After merging the tip tree, today's linux-next build (x86_64
> allmodconfig) produced these warnings:
> 
> In file included from arch/x86/vdso/vdso2c.c:161:0: 
> arch/x86/vdso/vdso2c.c: In function 'main': 
> arch/x86/vdso/vdso2c.h:118:6: warning: assuming signed overflow
> does not occur when assuming that (X + c) < X is always false
> [-Wstrict-overflow] In file included from
> arch/x86/vdso/vdso2c.c:165:0: arch/x86/vdso/vdso2c.h:118:6:
> warning: assuming signed overflow does not occur when assuming that
> (X + c) < X is always false [-Wstrict-overflow]
> 
> Probably introduced by commit e6577a7ce99a ("x86, vdso: Move the
> vvar area before the vdso text").
> 

This seems toxic.

I always wonder if we shouldn't use -fwrapv for the kernel...

	-hpa