From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752583Ab2A2Lik (ORCPT ); Sun, 29 Jan 2012 06:38:40 -0500 Received: from ozlabs.org ([203.10.76.45]:39884 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928Ab2A2Lij (ORCPT ); Sun, 29 Jan 2012 06:38:39 -0500 From: Rusty Russell To: Oleg Nesterov Cc: Tetsuo Handa , Andrew Morton , Arjan van de Ven , Tejun Heo , linux-kernel@vger.kernel.org Subject: Re: + kmod-avoid-deadlock-by-recursive-kmod-call.patch added to -mm tree In-Reply-To: <20120127143234.GA13056@redhat.com> References: <20120126175612.GA24011@redhat.com> <87ipjxdfbg.fsf@rustcorp.com.au> <20120127143234.GA13056@redhat.com> User-Agent: Notmuch/0.6.1-1 (http://notmuchmail.org) Emacs/23.3.1 (i686-pc-linux-gnu) Date: Sun, 29 Jan 2012 11:19:00 +1030 Message-ID: <87y5srbaf7.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 27 Jan 2012 15:32:34 +0100, Oleg Nesterov wrote: > On 01/27, Rusty Russell wrote: > > On Thu, 26 Jan 2012 18:56:12 +0100, Oleg Nesterov wrote: > > > Can't we simply kill khelper_wq and use system_unbound_wq instead? > > > > I'd prefer that, because then we'd hit the existing "too many modprobes" > > check. > > Hmm. Why? I mean, why do you think that s/khelper_wq/system_unbound_wq/ > leads to recursive __request_module's ? > > Note that that this patch (which adds kmod_thread_locker) can not limit > the recursive modprobe loop. > > > OK, yes, with system_unbound_wq we can hit this warning if we have > max_modprobes UMH_WAIT_EXEC's resulting in __request_module at the > same time, but probably this is good? Yes, that's what I'm saying. We already have a check against too many modprobes, it might be best to use it. Cheers, Rusty.