linux-kernel - Re: linux-next: build warning after merge of the char-misc tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <201302151807.46217.arnd@arndb.de>
Date:	Fri, 15 Feb 2013 18:07:46 +0000
From:	Arnd Bergmann <arnd@...db.de>
To:	Greg KH <greg@...ah.com>
Cc:	Stephen Rothwell <sfr@...b.auug.org.au>,
	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
	David Stevenson <david@...ncliff.com>
Subject: Re: linux-next: build warning after merge of the char-misc tree

On Friday 15 February 2013, Greg KH wrote:
> On Fri, Feb 15, 2013 at 04:26:57PM +1100, Stephen Rothwell wrote:
> > Hi all,
> > 
> > After merging the char-misc tree, today's linux-next build (x86_64
> > allmodconfig) produced this warning:
> > 
> > drivers/w1/slaves/w1_therm.c: In function 'w1_therm_read':
> > drivers/w1/slaves/w1_therm.c:245:15: warning: 'crc' may be used uninitialized in this function [-Wuninitialized]
> > 
> > Its a false positive, but it was introduced by commit 867ff9880d5d
> > ("w1_therm: Retries: remove old code add CRC")
> 
> I don't see that here with gcc 4.7.1, perhaps you need to upgrade your
> version of gcc to not show these false positives?

I see the same warning with gcc-4.6.3, 4.7.2 and 4.8.0-20130114 on ARM.

In case of 4.8, the output is

drivers/w1/slaves/w1_therm.c: In function 'w1_therm_read':
drivers/w1/slaves/w1_therm.c:245:15: warning: 'crc' may be used uninitialized in this function [-Wmaybe-uninitialized]
  c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
               ^

I actually see much more of these false positives with 4.7 and 4.8 than
I get with 4.6, which is the main reason for me to use 4.6 for my daily
builds. I agree that this particular false positive is an especially
dumb one and it would be good to not just shut up gcc by initializing
it, but I have no other idea what to do with the hundreds of such
warnings I get.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/