From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id A3B99AC2 for ; Thu, 9 Jul 2015 10:06:14 +0000 (UTC) Received: from mgwkm04.jp.fujitsu.com (mgwkm04.jp.fujitsu.com [202.219.69.171]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id E9FB7AA for ; Thu, 9 Jul 2015 10:06:13 +0000 (UTC) Received: from m3051.s.css.fujitsu.com (m3051.s.css.fujitsu.com [10.134.21.209]) by kw-mxoi2.gw.nic.fujitsu.com (Postfix) with ESMTP id 0F5FCAC03A7 for ; Thu, 9 Jul 2015 19:06:11 +0900 (JST) Message-ID: <559E477F.2040801@jp.fujitsu.com> Date: Thu, 09 Jul 2015 19:05:51 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 To: Jiri Kosina References: <559D4C35.6070709@hitachi.com> <559DE9E5.20204@jp.fujitsu.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: ksummit-discuss@lists.linuxfoundation.org Subject: Re: [Ksummit-discuss] [CORE TOPIC] live patching List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 2015/07/09 18:56, Jiri Kosina wrote: > On Thu, 9 Jul 2015, Kamezawa Hiroyuki wrote: > >> I'm sorr if this is off-topic. >> >> I think the problem of "freezer v.s. FUSE" will happen if we neet to >> stop user proceesses. AFAIK, the problem is a deadlock that fuse daemon >> freezes even while its client wating for a reply. >> >> example) >> client -> page-fault -> GUP -> fuse daemon -> gethostbyname() -> nscd.8 >> >> We can't detect this kind of dependency if we need to freeze userland. > > Freezing of userspace is happening every time system goes through > hibernation. > yes. so, we need to find a way for fixing deadlock or avoiding it. AFAIK, Hibernation+FUSE problem has been being reported since several years ago. I think there are some workaround to stop using FUSE before hibernation by hand or script or systemd but it seems not to be an option for live patching. Thanks, -Kame