From: Andi Kleen <ak@suse.de>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Notifier chains are unsafe
Date: 26 Oct 2005 01:43:16 +0200 [thread overview]
Message-ID: <p733bmp40yz.fsf@verdi.suse.de> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0510241634410.4448-100000@iolanthe.rowland.org>
Alan Stern <stern@rowland.harvard.edu> writes:
> Has anyone been bothered by the fact that notifier chains are not safe
> with regard to registration and unregistration while the chain is in use?
> The notifier_chain_register and notifier_chain_unregister routines have
> writelock protections, but the corresponding readlock is never taken!
If you add locks to the reader make sure it is only taken
if the list is non empty. Otherwise you will add unacceptable
overhead to some fast paths.
Better would be likely to use RCU.
-Andi
next prev parent reply other threads:[~2005-10-25 23:43 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-24 20:48 Notifier chains are unsafe Alan Stern
2005-10-25 16:59 ` Joe Seigh
2005-10-25 23:30 ` Chandra Seetharaman
2005-10-26 18:46 ` Alan Stern
2005-10-26 19:05 ` Andreas Kleen
2005-10-26 20:40 ` Alan Stern
2005-10-26 21:44 ` Andi Kleen
2005-10-26 23:20 ` Chandra Seetharaman
2005-10-27 1:17 ` Joe Seigh
2005-10-28 1:36 ` Chandra Seetharaman
2005-10-27 14:13 ` Alan Stern
2005-10-26 22:40 ` Chandra Seetharaman
2005-10-27 15:28 ` Alan Stern
2005-10-27 20:43 ` Chandra Seetharaman
2005-10-27 21:21 ` Alan Stern
2005-10-27 23:02 ` Chandra Seetharaman
2005-10-28 0:48 ` Keith Owens
2005-10-28 1:34 ` Chandra Seetharaman
2005-10-28 14:23 ` Alan Stern
2005-10-28 22:15 ` Chandra Seetharaman
2005-10-29 14:51 ` Alan Stern
2005-10-31 22:22 ` Chandra Seetharaman
2005-11-01 15:24 ` Alan Stern
2005-11-01 20:20 ` Chandra Seetharaman
2005-11-01 21:20 ` Alan Stern
2005-11-02 9:50 ` Keith Owens
2005-11-02 16:03 ` Alan Stern
[not found] ` <mailman.1130460600.30060.linux-kernel2news@redhat.com>
2005-10-28 4:35 ` Pete Zaitcev
2005-10-25 23:43 ` Andi Kleen [this message]
2005-10-26 0:01 ` Chandra Seetharaman
2005-10-26 17:11 ` Andreas Kleen
2005-10-27 2:46 ` Herbert Xu
2005-10-29 12:25 ` Joe Seigh
2005-10-26 6:11 ` Keith Owens
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