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Date: Thu, 10 Nov 2011 01:11:07 +0000
From: Dave Haywood <tla@oak.selfip.net>
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To: Borislav Petkov <bp@alien8.de>
CC: Steven Rostedt <rostedt@goodmis.org>,
        Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: Build warning: kernel/trace/trace.c (v3.2-rc1-90-g19e0baf)
References: <4EBA3E3E.9060402@oak.selfip.net> <20111109113303.GA18508@gere.osrc.amd.com>
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On 09/11/2011 11:33, Borislav Petkov wrote:

> On Wed, Nov 09, 2011 at 08:47:58AM +0000, Dave Haywood wrote:
>> Hi,
>>
>>   Noticed this new warning in the build of kernel v3.2-rc1-90-g19e0baf:
>>
>>   CC      kernel/trace/trace.o
>> kernel/trace/trace.c: In function 'tracing_mark_write':
>> kernel/trace/trace.c:3644:8: warning: 'page2' may be used uninitialized in this function
> That has to be gcc 4.5.x something. 4.6 is smarter in that aspect:
Correct, version is:

$ gcc --version

gcc (Gentoo Hardened 4.5.3-r1 p1.0, pie-0.4.5) 4.5.3

Copyright (C) 2010 Free Software Foundation, Inc.

This is free software; see the source for copying conditions.  There is NO

warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

>
> $ make CC=gcc-4.6 kernel/trace/trace.o
>   CHK     include/linux/version.h
>   UPD     include/linux/version.h
>   CHK     include/generated/utsrelease.h
>   UPD     include/generated/utsrelease.h
>   CC      kernel/bounds.s
>
>   ...
>
>   HOSTLD  scripts/mod/modpost
>   CC      kernel/trace/trace.o
> $ make CC=gcc-4.5 kernel/trace/trace.o
>   CHK     include/linux/version.h
>   CHK     include/generated/utsrelease.h
>   CC      kernel/bounds.s
>
>   ...
>
>   HOSTLD  scripts/mod/modpost
>   CC      kernel/trace/trace.o
> kernel/trace/trace.c: In function ‘tracing_mark_write’:
> kernel/trace/trace.c:3644:8: warning: ‘page2’ may be used uninitialized in this function
>
> HTH
>