From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754016AbcEQM76 (ORCPT ); Tue, 17 May 2016 08:59:58 -0400 Received: from forward7p.cmail.yandex.net ([87.250.241.192]:43159 "EHLO forward7p.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750711AbcEQM75 (ORCPT ); Tue, 17 May 2016 08:59:57 -0400 From: okhalzov@team.vestbery.com To: Paolo Bonzini , Linus Torvalds , Andy Lutomirski Cc: Marcelo Tosatti , the arch/x86 maintainers , Linux Kernel Mailing List , Taloth Saldono Subject: Re:Please review arch/x86/kernel/pvclock.c to fix Docker/Mono crashes in new Kernels MIME-Version: 1.0 Message-Id: <4696251463489989@web4g.yandex.ru> X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Tue, 17 May 2016 15:59:49 +0300 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=koi8-r Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paolo, the crashes occure on bare-metal (3.13.0-49-generic) and Docker is inside of VMWare vCenter (4.2.0-35-generic). On 3.19.0-25-generic with some highload (200 client requests simultaneously) in Docker inside of VMWare vCenter it doesn't crash. -- Олег Хальзов SDE Vestbery 17.05.2016, 14:06, "Paolo Bonzini" : > On 16/05/2016 20:56, Linus Torvalds wrote: > >> On Mon, May 16, 2016 at 11:37 AM, Andy Lutomirski wrote: >> >>> All of those fixes were intended to fix incorrect times being >>> reported, not segfaults. Weird. >> >> I'm assuming it's "time going backwards". I can easily see that >> causing segfaults. > > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1450584 says the > crashes occurs "more frequently on a vbox vm with multiple CPUs > configured". If vbox tells the VM to use the vdso when it shouldn't > (because the TSC is not stable on the host), bad things could happen. > > However, based on the Xamarin bug comments and > http://lists.ximian.com/pipermail/mono-devel-list/2015-August/043181.html, > it looks like vbox after all doesn't use pvclock and the trigger seems > to be https://github.com/torvalds/linux/commit/c70e1b475f37: > > With __always_inline on vread_pvclock, mono crashed. With noinline on > vread_pvclock, mono doesn't crash. Weirdest part is that the pvclock > isn't even used during my tests. > > Oleg, what is your environment exactly? You mentioned Docker, but are > you also virtualizing and if so what is your hypervisor? > > Taloth, do you know if it can it be reproduced under Xen or KVM or > bare-metal? I'd trust them more than VirtualBox regarding timekeeping. > I saw Amazon Linux mentioned in the mono mailing list archives which > would point to Xen. Xen doesn't use the pvclock vdso code either, though. > > Thanks, > > Paolo