linux-kernel - Re: [PATCH] x86: Drop redundant memory-block sizing code

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]

Date:	Thu, 06 Nov 2014 19:10:45 +0800
From:	Daniel J Blueman <daniel@...ascale.com>
To:	Borislav Petkov <bp@...en8.de>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Yinghai Lu <yinghai@...nel.org>, x86@...nel.org,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	Steffen Persvold <sp@...ascale.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH] x86: Drop redundant memory-block sizing code

On 11/06/2014 06:40 PM, Borislav Petkov wrote:
> On Thu, Nov 06, 2014 at 06:33:40PM +0800, Daniel J Blueman wrote:
>> As the first check for 64GB or larger memory returns a 2GB memory block size
>> in that case, the following check for less than 64GB will always evaluate
>> true, leading to unreachable code.
>
> I'm reading this as this code is never running on systems < 64GB. Why is
> that so?

Let me clarify that "Leading to" didn't mean "executing":

"As the first check for 64GB or larger memory returns a 2GB memory block 
size in that case, the following check for less than 64GB will always 
evaluate true and return MIN_MEMORY_BLOCK_SIZE, leading to unreachable code.

Remove the second and unnecessary condition and the code in the 
remainder of the function, as it therefore can't be reached."

Sheesh. Even Shakespeare would have trouble writing a exemplary changelog.

Thanks,
   Daniel
-- 
Daniel J Blueman
Principal Software Engineer, Numascale
--
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/