linux-kernel - RE:(2) [PATCH v2] md/bitmap: Avoid protection error writing bitmap page with block integrity

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: <20230731074902epcms2p5383ba1e030b5c79730fa14393bb1cdb5@epcms2p5>
Date:   Mon, 31 Jul 2023 16:49:02 +0900
From:   Jinyoung Choi <j-young.choi@...sung.com>
To:     Christoph Hellwig <hch@...radead.org>
CC:     "song@...nel.org" <song@...nel.org>,
        "linux-raid@...r.kernel.org" <linux-raid@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "pmenzel@...gen.mpg.de" <pmenzel@...gen.mpg.de>
Subject: RE:(2) [PATCH v2] md/bitmap: Avoid protection error writing bitmap
 page with block integrity

> On Thu, Jul 20, 2023 at 06:29:57PM +0900, Jinyoung Choi wrote:
> > Changing the bitmap page is also possible on the page where the DMA is
> > being performed or scheduled in the MD.
> 
> Are you guys actually using the whacky bitmap feature?  If so, this
> really is the least of our problems and you need to invest some real
> work into it to get it off ->bmap and into using ->read_iter and
> ->write_iter.  Right now Song has a series from me queued up to
> deprecated it.
> 
> I also don't think a simple wait for existing writers prevents you
> from other modifications, but maybe I'm issing something.

Hi, Christoph.

I think the way to write bitmap page like you should be changed.
This patch is a simple workaround in the current system.

I will check the patches you provided for bitmap processing.

Thank you for your review.

Best Regards,
Jinyoung.