Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752123AbdIMJBD (ORCPT ); Wed, 13 Sep 2017 05:01:03 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:34599 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751985AbdIMJA7 (ORCPT ); Wed, 13 Sep 2017 05:00:59 -0400 X-Google-Smtp-Source: AOwi7QCwsVGRKWdum5j70LTCEX3lJt3i6X3ymu55KTYd2dr5/3Zw2pCsMz/GS8T9XCHj4GochlcPzw== Date: Wed, 13 Sep 2017 11:00:56 +0200 From: Ingo Molnar To: KY Srinivasan Cc: Dan Carpenter , "x86@kernel.org" , "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" , "devel@linuxdriverproject.org" , "olaf@aepfle.de" , "apw@canonical.com" , "jasowang@redhat.com" , "tglx@linutronix.de" , "hpa@zytor.com" Subject: Re: [PATCH 1/1] x86/hyper-V: Allocate the IDT entry early in boot Message-ID: <20170913090056.nveesthowrsjytm6@gmail.com> References: <20170908231557.2419-1-kys@exchange.microsoft.com> <20170909105428.osqbcf4gnibobpse@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1328 Lines: 39 * KY Srinivasan wrote: > > > > -----Original Message----- > > From: Dan Carpenter [mailto:dan.carpenter@oracle.com] > > Sent: Saturday, September 9, 2017 4:04 AM > > To: KY Srinivasan > > Cc: x86@kernel.org; gregkh@linuxfoundation.org; linux- > > kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de; > > apw@canonical.com; jasowang@redhat.com; tglx@linutronix.de; > > hpa@zytor.com; mingo@kernel.org > > Subject: Re: [PATCH 1/1] x86/hyper-V: Allocate the IDT entry early in boot > > > > On Fri, Sep 08, 2017 at 04:15:57PM -0700, kys@exchange.microsoft.com > > wrote: > > > From: "K. Y. Srinivasan" > > > > > > Allocate the hypervisor callback IDT entry early in the boot sequence. > > > > > > > I'm guessing this fixes a NULL dereference or something? The changelog > > doesn't really say why we are doing this. > > The changelog does say what we are doing - allocating the IDT entry early in the boot sequence. But the question was the 'why', not the 'what' - so Dan's question is fully justified ... > The current code would allocate the entry as part of registering the handler > when vmbus driver loaded and this caused a problem for the cleanup Thomas had > implemented. I've put this explanation into the changelog. Thanks, Ingo