linux-kernel - Re: [PATCH 1/8] lockdep: fix recursive read lock validation

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: <1209488643.6433.14.camel@lappy>
Date:	Tue, 29 Apr 2008 19:04:03 +0200
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Bart Van Assche <bart.vanassche@...il.com>
Cc:	ego@...ibm.com, linux-kernel@...r.kernel.org,
	Zdenek Kabelac <zdenek.kabelac@...il.com>,
	Oleg Nesterov <oleg@...sign.ru>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Srivatsa Vaddagiri <vatsa@...ibm.com>
Subject: Re: [PATCH 1/8] lockdep: fix recursive read lock validation

On Tue, 2008-04-29 at 18:29 +0200, Bart Van Assche wrote:
> On Tue, Apr 29, 2008 at 6:15 PM, Peter Zijlstra <a.p.zijlstra@...llo.nl> wrote:
> >
> >  > Or: whether or not to allow a sequence like "rlock(a); rlock(b);
> >  > runlock(b); runlock(a); rlock(b); rlock(a);" is something we can
> >  > choose. We do not have to forbid this sequence -- we can choose
> >  > whether or not we allow this sequence.
> >
> >  I'm utterly confused now; I never argued that it would get deadlocks;
> >  and I said I choose to not allow it from a lockdep pov. What else do you
> >  want?
> 
> So we both agree that the statement in the original e-mail (by Gautham
> R Shenoy) is wrong ? The original e-mail stated that obtaining reader
> locks in an inconsistent order is wrong.

I think the critical part is:

> It really is invalid when considered against write locks.

Aside from that it just states that inversion of lock order will be
treated as invalid - even for read locks.



--
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/