linux-kernel - Re: [PATCH] drivers: regmap: bugfix in regcache-rbtree.c

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:	Wed, 21 Aug 2013 16:24:00 +0200
From:	David Jander <david.jander@...tonic.nl>
To:	Mark Brown <broonie@...nel.org>
Cc:	Dimitris Papastamos <dp@...nsource.wolfsonmicro.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drivers: regmap: bugfix in regcache-rbtree.c

On Wed, 21 Aug 2013 15:08:16 +0100
Mark Brown <broonie@...nel.org> wrote:

> On Wed, Aug 21, 2013 at 03:14:23PM +0200, David Jander wrote:
> 
> > Here's the explanation:
> 
> > 1. If a driver initializes a regmap with a RB-tree cache, and starts
> > writing to registers in some arbitrary order, you might get overlapping
> > rbnodes: Suppose I have this rb-tree (a real case I happen to have):
> 
> > # cat /sys/kernel/debug/regmap/1-000a/rbtree
> > 2-19 (24)
> > 4-1b (24)
> 
> Like I say this isn't supposed to be the case in the first place, those
> two nodes should be being merged - what we need to understand is where
> the overlapping nodes came from.

As I said in my last e-mail just a few seconds ago, it does happen when:

1. 4-1b is cached and 2-19 isn't yet.

2. A write access to register 2 occurs.

Hope this helps.

Best regards,

-- 
David Jander
Protonic Holland.
--
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/