From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763553AbZLQBBY (ORCPT ); Wed, 16 Dec 2009 20:01:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763530AbZLQBBP (ORCPT ); Wed, 16 Dec 2009 20:01:15 -0500 Received: from cantor.suse.de ([195.135.220.2]:52277 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763499AbZLQBBL (ORCPT ); Wed, 16 Dec 2009 20:01:11 -0500 Date: Wed, 16 Dec 2009 17:00:41 -0800 From: Greg KH To: Al Viro Cc: linux-kernel@vger.kernel.org, Kay Sievers Subject: Re: devtmpfs [censored] oddities Message-ID: <20091217010041.GA6479@suse.de> References: <20091216080431.GF14381@ZenIV.linux.org.uk> <20091217003922.GB4863@suse.de> <20091217004643.GR14381@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091217004643.GR14381@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 17, 2009 at 12:46:43AM +0000, Al Viro wrote: > On Wed, Dec 16, 2009 at 04:39:22PM -0800, Greg KH wrote: > > On Wed, Dec 16, 2009 at 08:04:31AM +0000, Al Viro wrote: > > > May I respectfully suggest that a blocking operation (such as > > > kstrdup with GFP_KERNEL, or grabbing a mutex, or, say it, pathname resolution) > > > is not quite the thing to do while holding an rwlock? > > > > > > As it is, any device_add() is an embarrassingly obvious deadlock > > > waiting to happen... > > > > Thomas has posted a patch to fix this now. > > > > Sorry for not catching it sooner, we should just delete the rwlocks so > > no one tries to ever use it again. > > Say again? Why would we delete rwlocks? Sorry, no _new_ use of rwlocks should be added, generally they are used incorrectly, like this one was. thanks, greg k-h