linux-kernel - Re: [PATCH] rbtree: undo augmented damage -v2

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: <1275551314.27810.34894.camel@twins>
Date:	Thu, 03 Jun 2010 09:48:34 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
Cc:	Venkatesh Pallipadi <venki@...gle.com>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"hpa@...or.com" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"linux-tip-commits@...r.kernel.org" 
	<linux-tip-commits@...r.kernel.org>,
	Fabio Checconi <fabio@...dalf.sssup.it>
Subject: Re: [PATCH] rbtree: undo augmented damage -v2

On Thu, 2010-06-03 at 09:13 +0200, Peter Zijlstra wrote:
> On Wed, 2010-06-02 at 14:11 -0700, Suresh Siddha wrote:
> >       P                       SL
> >     /  \                     /  \
> >    N    S       --->        N    S
> >   /   /  \                 /      \
> >  C   SL  SR               C        SR
> > 
> > If P needs to be removed, we need to re-augment S also in this case,
> > right? It looks like we are not handling this case.
> 
> 
> rb_augment_erase_begin(P) will return S if I read the code right, so
> rb_augment_path(S) will the re-augment S, SL, N.

To be more explicit: P has two children, so we select the next entry,
SL, as its substitute. Since SL doesn't have a right child we select its
parent, S.

If SL were to represent a subtree with a right child, then we'd select
that, lets call it SLR. SLR would then end up being a direct descendant
of S, and hence rb_augment_path(SLR) would still pass S on its way up.


--
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/