From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:36646 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932797AbbI2R5M (ORCPT ); Tue, 29 Sep 2015 13:57:12 -0400 Date: Tue, 29 Sep 2015 19:57:10 +0200 From: Greg Kroah-Hartman To: Andy Lutomirski Cc: "linux-kernel@vger.kernel.org" , stable , Andy Lutomirski , Steven Rostedt , Borislav Petkov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: Re: [PATCH 3.14 79/84] x86/nmi/64: Switch stacks on userspace NMI entry Message-ID: <20150929175710.GC12540@kroah.com> References: <20150929145330.924730721@linuxfoundation.org> <20150929145334.482419451@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: On Tue, Sep 29, 2015 at 10:25:52AM -0700, Andy Lutomirski wrote: > On Tue, Sep 29, 2015 at 8:19 AM, Greg Kroah-Hartman > wrote: > > 3.14-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Andy Lutomirski > > > > commit 9b6e6a8334d56354853f9c255d1395c2ba570e0a upstream. > > > > Returning to userspace is tricky: IRET can fail, and ESPFIX can > > rearrange the stack prior to IRET. > > Just a heads up: under very strange circumstances (most likely > requires booting with paravirt-noreplace, which is hopefully only used > by Sasha), this causes a regression that's fixed by > 83c133cf11fb0e68a51681447e372489f052d40e. I'm not 100% sure that the > regression is observable at all, because the same strange > configuration may also hit the bug fixed by > fc57a7c68020dcf954428869eafd934c0ab1536f before the regression can > trigger. > > Anyway, you've been warned. I wouldn't worry too much about it, though. Thanks, that patch is still in my queue for future stable kernels, so it should trickle down soon. thanks, greg k-h