From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Anzinger Subject: Re: [PATCH 3/3] Add disk hotswap support to libata RESEND #2 Date: Tue, 23 Aug 2005 15:56:16 -0700 Message-ID: <430BA990.9090807@mvista.com> References: <355e5e5e05080103021a8239df@mail.gmail.com> <4789af9e050823124140eb924f@mail.gmail.com> <4789af9e050823154364c8e9eb@mail.gmail.com> Reply-To: george@mvista.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4789af9e050823154364c8e9eb@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Jim Ramsay Cc: Linux-ide , Lukasz Kosewski , Jeff Garzik , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-ide@vger.kernel.org Jim Ramsay wrote: > On 8/23/05, Jim Ramsay wrote: > >>Then I must have found an undocumented feature! I've applied this set >>of patches to a 2.6.11 kernel (with few problems) and ran into a bunch >>of "scheduling while atomic" errors when hotplugging a drive, culprit >>being probably scsi_sysfs.c where scsi_remove_device locks a mutex, or >>perhaps when it then calls class_device_unregister, which does a >>'down_write'. > > > After further debugging, it appears that the problem is the debounce > timer in libata-core.c. > > Timers appear to operate in an atomic context, so timers should not be > allowed to call scsi_remove_device, which eventually schedules. > > Any suggestions on the best way to fix this? Workqueue, perhaps. > -- George Anzinger george@mvista.com HRT (High-res-timers): http://sourceforge.net/projects/high-res-timers/