From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 In-Reply-To: <20170105095706.GA15566@lst.de> References: <1483507505-26797-1-git-send-email-hch@lst.de> <1483507505-26797-2-git-send-email-hch@lst.de> <20170105095706.GA15566@lst.de> From: =?UTF-8?B?546L6YeR5rWm?= Date: Thu, 5 Jan 2017 11:37:46 +0100 Message-ID: Subject: Re: [PATCH] virtio_blk: avoid DMA to stack for the sense buffer To: Christoph Hellwig Cc: Jens Axboe , mst@redhat.com, jasowang@redhat.com, linux-block@vger.kernel.org, virtualization@lists.linux-foundation.org, LKML Content-Type: text/plain; charset=UTF-8 List-ID: 2017-01-05 10:57 GMT+01:00 Christoph Hellwig : > On Wed, Jan 04, 2017 at 04:47:03PM +0100, =E7=8E=8B=E9=87=91=E6=B5=A6 wro= te: >> This sounds scary. >> Could you share how to reproduce it, this should go into stable if >> it's the case. > > Step 1: Build your kernel with CONFIG_VMAP_STACK=3Dy > Step 2: issue a SG_IO ioctl, e.g. sg_inq /dev/vda > Thanks, so it's only relevant to kernel > 4.9, as CONFIG_VMAP_STACK only introduced in 4.9 kernel. Regards, Jinpu From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758105AbdAEKiI (ORCPT ); Thu, 5 Jan 2017 05:38:08 -0500 Received: from mail-yw0-f194.google.com ([209.85.161.194]:36184 "EHLO mail-yw0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752177AbdAEKhr (ORCPT ); Thu, 5 Jan 2017 05:37:47 -0500 MIME-Version: 1.0 In-Reply-To: <20170105095706.GA15566@lst.de> References: <1483507505-26797-1-git-send-email-hch@lst.de> <1483507505-26797-2-git-send-email-hch@lst.de> <20170105095706.GA15566@lst.de> From: =?UTF-8?B?546L6YeR5rWm?= Date: Thu, 5 Jan 2017 11:37:46 +0100 Message-ID: Subject: Re: [PATCH] virtio_blk: avoid DMA to stack for the sense buffer To: Christoph Hellwig Cc: Jens Axboe , mst@redhat.com, jasowang@redhat.com, linux-block@vger.kernel.org, virtualization@lists.linux-foundation.org, LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id v05AeglZ018212 2017-01-05 10:57 GMT+01:00 Christoph Hellwig : > On Wed, Jan 04, 2017 at 04:47:03PM +0100, 王金浦 wrote: >> This sounds scary. >> Could you share how to reproduce it, this should go into stable if >> it's the case. > > Step 1: Build your kernel with CONFIG_VMAP_STACK=y > Step 2: issue a SG_IO ioctl, e.g. sg_inq /dev/vda > Thanks, so it's only relevant to kernel > 4.9, as CONFIG_VMAP_STACK only introduced in 4.9 kernel. Regards, Jinpu