linux-kernel - Re: [PATCH 3/3] checkpatch: Emit a warning when decimal values are used

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] [day] [month] [year] [list]

Message-ID: <20121101114301.GB32532@liondog.tnic>
Date:	Thu, 1 Nov 2012 12:43:01 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Pavel Machek <pavel@....cz>, Joe Perches <joe@...ches.com>,
	Andy Whitcroft <apw@...onical.com>,
	Adil Mujeeb <mujeeb.adil@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] checkpatch: Emit a warning when decimal values are
 used

On Wed, Oct 31, 2012 at 03:49:08PM -0700, Andrew Morton wrote:
> Joe means floating point.  I suggest that the patchset be reworked,
> using s/decimal/float/g.
> 
> 
> The kernel does have floating point constants, in various graphics
> drivers, iirc.  They are used in places where the floatiness gets
> handled at complation time.  Along the lines of:
> 
> 	int foo = 1.1 * 2.2;
> 
> And I suppose that's an OK thing to do.  We could instead do
> 
> 	int foo = 2;	/* 1.1 * 2.2 */
> 
> but that's taking away a programmer convenience for no good reason. 
> It would be highly inconvenient if the "1.1" was in fact a #define in
> some other file, or a Kconfig string.
> 
> 
> 
> That being said, I guess it's a worthwhile thing for checkpatch to warn
> about.  Hopefully the programmer will say "well thanks, but I meant to
> do that".
> 
> A much better solution would be to arrange for the kernel to fail to
> compile (or to fail to link) if floats are used.  That way, people
> could continue to use floats within their compile-time scalar
> expressions without getting harrassed by checkpatch.  But I don't know
> how to arrange this.

Run git grep on the source before compiling... Expensive though.

Also, Joe, I think you should add Andrew's explanation to the commit
message so that it is clear what that check is for. Or maybe even as a
comment above the check itself in checkpatch.pl.

Thanks.

-- 
Regards/Gruss,
    Boris.
--
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/