Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754927Ab1EFBP0 (ORCPT ); Thu, 5 May 2011 21:15:26 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:39249 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754442Ab1EFBPZ (ORCPT ); Thu, 5 May 2011 21:15:25 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=vrfy.org; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=N+9ba5Cxyp7zzpucvOfQClwlDWp3YJ+1BO1/29qQ6pad3RlDdl6IcHH9bO/93JU4yt WKx/0Xwa8UEBU5aIRsjLLUjcIC9DMAHGi+hF2dgAdOdQxd4PqCvdnjrO7Lc+9jPcVqtH lpFmLI7Y1YY6Aj4abT7YK/4Uu8xRPQM/EA8xw= MIME-Version: 1.0 In-Reply-To: <20110505202758.GA12812@kroah.com> References: <1304595126.1284.3.camel@zag> <20110505202758.GA12812@kroah.com> From: Kay Sievers Date: Fri, 6 May 2011 03:15:10 +0200 Message-ID: Subject: Re: [PATCH] reboot: disable usermodehelper to prevent fs access To: Greg KH Cc: linux-kernel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1777 Lines: 39 On Thu, May 5, 2011 at 22:27, Greg KH wrote: > On Thu, May 05, 2011 at 01:32:05PM +0200, Kay Sievers wrote: >> From: Kay Sievers >> Subject: [PATCH] reboot: disable usermodehelper to prevent fs access >> >> In case CONFIG_UEVENT_HELPER_PATH is not set to "", which it >> should be on every system, the kernel forks processes during >> shutdown, which try to access the rootfs, even when the >> binary does not exist. It causes exceptions and long delays in >> the disk driver, which gets read requests at the time it tries >> to shut down the disk. >> >> This patch disables all kernel-forked processes during reboot to >> allow a clean poweroff. > > Should this also be backported to the -stable kernels as people are > hitting this problem already today, right? If it survives fine, I guess it's nothing that will hurt us in -stable. Suspend/hibernate does the same thing for similar reasons since a while. Nothing really should use /sbin/hotplug anymore. It just does not scale with what we do today with kernel devices. Old udev SYSV init scripts or initramfs used to disable it at bootup. But recent init systems just don't care anymore. So it just popped up with systemd, where udev is a plain native service without "legacy disablement". So, it might be nice for recently released kernels, on the other hand it will not cause any problems or data-loos, just a nasty delay at shutdown, because of a kernel config option UEVENT_HELPER_PATH that is set wrong for today's systems. Kay -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/