From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate8.de.ibm.com (8.13.8/8.13.8) with ESMTP id m9OJKWOn389570 for ; Fri, 24 Oct 2008 19:20:32 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m9OJKWeZ3838094 for ; Fri, 24 Oct 2008 21:20:32 +0200 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m9OJKVwp018144 for ; Fri, 24 Oct 2008 21:20:32 +0200 Date: Fri, 24 Oct 2008 21:20:31 +0200 From: Heiko Carstens Subject: Re: [RFC][PATCH] lru_add_drain_all() don't use schedule_on_each_cpu() Message-ID: <20081024192031.GA4155@osiris.boeblingen.de.ibm.com> References: <2f11576a0810210851g6e0d86benef5d801871886dd7@mail.gmail.com> <2f11576a0810211018g5166c1byc182f1194cfdd45d@mail.gmail.com> <20081023235425.9C40.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081023235425.9C40.KOSAKI.MOTOHIRO@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org Return-Path: To: KOSAKI Motohiro Cc: Nick Piggin , linux-kernel@vger.kernel.org, Hugh Dickins , Andrew Morton , Linus Torvalds , Rik van Riel , Lee Schermerhorn , linux-mm@kvack.org, Christoph Lameter List-ID: On Fri, Oct 24, 2008 at 12:00:17AM +0900, KOSAKI Motohiro wrote: > Hi Heiko, > > This bug is caused by folloing dependencys. > > > > some VM place has > > mmap_sem -> kevent_wq > > > > net/core/dev.c::dev_ioctl() has > > rtnl_lock -> mmap_sem (*) almost ioctl has > > copy_from_user() and it cause page fault. > > > > linkwatch_event has > > kevent_wq -> rtnl_lock > > > > > > So, I think VM subsystem shouldn't use kevent_wq because many driver > > use ioctl and work queue combination. > > then drivers fixing isn't easy. > > > > I'll make the patch soon. > > My box can't reproduce this issue. > Could you please test on following patch? Your patch seems to fix the issue. At least I don't see the warning anymore ;) Thanks, Heiko -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org