From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752639Ab1HCNpK (ORCPT ); Wed, 3 Aug 2011 09:45:10 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:58093 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751056Ab1HCNpI (ORCPT ); Wed, 3 Aug 2011 09:45:08 -0400 From: Richard Weinberger To: Kay Sievers Subject: Re: [PATCH] shm: fix a race between shm_exit() and shm_init() Date: Wed, 3 Aug 2011 15:45:00 +0200 User-Agent: KMail/1.13.7 (Linux/2.6.37.6-0.5-desktop; KDE/4.6.5; x86_64; ; ) Cc: Thadeu Lima de Souza Cascardo , linux-kernel@vger.kernel.org, marc.zyngier@arm.com, manuel.lauss@googlemail.com, torvalds@linux-foundation.org, akpm@linux-foundation.org, segoon@openwall.com, gregkh@suse.de References: <20110803113033.1c3c6960@taxman.wild-wind.fr.eu.org> <20110803131323.GC2773@nautilus.holoscopio.com> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201108031545.01122.richard@nod.at> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mittwoch 03 August 2011 15:33:27 Kay Sievers wrote: > On Wed, Aug 3, 2011 at 15:13, Thadeu Lima de Souza Cascardo > > wrote: > > As Marc Zyngier has pointed out, the culprit is driver_init, which > > calls devices_init. I'd say other calls from driver_init also call into > > kset and kobject, which will dispatch uevent helper. > > > > I tried to reproduce the problem using UML and only was successful after > > setting CONFIG_UEVENT_HELPER_PATH. I guess we could obsolete this > > feature and plan its removal soon. Is anybody still using this? > > Forking binaries from the kernel for frequent events is something > fundamentally wrong to do. It is not even rate-limited or has any > upper bounds. It is known to create out-of-memory situations on > machines with many devices and tiny RAM. Configs that virtualizations > with many guests use pretty often. They can not even bootup with > /sbin/hotplug enabled then. > > It would be nice to remove that broken thing, no common system or > distro uses it since quite some years now. But I wouldn't be surprised > if some people still use it for whatever hack they need locally. > True. I'll remove CONFIG_UEVENT_HELPER_PATH from UML's defconfig. Thanks, //richard