linux-kernel - Re: [PATCH 1/3] posix-timers: remove idr

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: <20110610204428.GB10930@one.firstfloor.org>
Date:	Fri, 10 Jun 2011 22:44:28 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	tglx@...utronix.de, Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 1/3] posix-timers: remove idr_lock

On Fri, Jun 10, 2011 at 10:40:38PM +0200, Eric Dumazet wrote:
> Le vendredi 10 juin 2011 à 13:13 -0700, Andi Kleen a écrit :
> > From: Andi Kleen <ak@...ux.intel.com>
> > 
> > idr_lock is only used to protect the global posix_timers idr,
> > but idr does its own locking (or RCUing) anyways and doesn't
> > need it. So remove it.
> 
> Are you sure of this assertion Andi ?
> 
> I believe we need an external synchronization before calling
> idr_remove() / idr_get_new()

idr has its own lock and from a quick check it seemed to always
take it when needed. Also ipc/* don't take a lock for this as far
as I can see, and I think RCU idr was designed for that.

-Andi
--
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/