linux-kernel - Re: [tip:locking/urgent] compiler, atomics: Provide READ_ONCE

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: <20151014162055.GH3816@twins.programming.kicks-ass.net>
Date:	Wed, 14 Oct 2015 18:20:55 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Dmitry Vyukov <dvyukov@...gle.com>
Cc:	Paul McKenney <paulmck@...ux.vnet.ibm.com>,
	tip-bot for Andrey Ryabinin <tipbot@...or.com>,
	linux-tip-commits@...r.kernel.org,
	kasan-dev <kasan-dev@...glegroups.com>,
	Ingo Molnar <mingo@...nel.org>,
	Kostya Serebryany <kcc@...gle.com>,
	Borislav Petkov <bp@...en8.de>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Sasha Levin <sasha.levin@...cle.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Wolfram Gloger <wmglo@...t.med.uni-muenchen.de>,
	Andrey Konovalov <andreyknvl@...gle.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Alexander Potapenko <glider@...gle.com>
Subject: Re: [tip:locking/urgent] compiler, atomics: Provide
 READ_ONCE_NOCHECK ()

On Wed, Oct 14, 2015 at 06:18:58PM +0200, Dmitry Vyukov wrote:
> 
> Well, if another thread writes it byte-by-byte, it pretty much does
> not matter how you read it.
> Note that I said "at least one access is not atomic". If both are
> atomic, then this is, of course, legal. And KTSAN considers
> READ/WRITE_ONCE as atomic operations.

OK, then I'm confused on what exactly the annotation does, but less
worried.
--
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/