linux-kernel - Re: [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter

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: <YSrlq41Ytw7q8fCR@casper.infradead.org>
Date:   Sun, 29 Aug 2021 02:40:59 +0100
From:   Matthew Wilcox <willy@...radead.org>
To:     Tony Luck <tony.luck@...el.com>
Cc:     Al Viro <viro@...iv.linux.org.uk>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andreas Gruenbacher <agruenba@...hat.com>,
        Christoph Hellwig <hch@...radead.org>,
        "Darrick J. Wong" <djwong@...nel.org>, Jan Kara <jack@...e.cz>,
        cluster-devel <cluster-devel@...hat.com>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        ocfs2-devel@....oracle.com, Borislav Petkov <bp@...en8.de>,
        X86-ML <x86@...nel.org>
Subject: Re: [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter_writeable

On Sat, Aug 28, 2021 at 03:20:58PM -0700, Tony Luck wrote:
> On Sat, Aug 28, 2021 at 3:12 PM Al Viro <viro@...iv.linux.org.uk> wrote:
> > BTW, is #MC triggered on stored to a poisoned cacheline?  Existence of CLZERO
> > would seem to argue against that...
> 
> No #MC on stores. Just on loads. Note that you can't clear poison
> state with a series of small writes to the cache line. But a single
> 64-byte store might do it (architects didn't want to guarantee that
> it would work when I asked about avx512 stores to clear poison
> many years ago).

Dave Jiang thinks MOVDIR64B clears poison.

http://archive.lwn.net:8080/linux-kernel/157617505636.42350.1170110675242558018.stgit@...ang5-desk3.ch.intel.com/