Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932787AbdDGSem (ORCPT ); Fri, 7 Apr 2017 14:34:42 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34086 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751383AbdDGSee (ORCPT ); Fri, 7 Apr 2017 14:34:34 -0400 Date: Fri, 7 Apr 2017 20:34:30 +0200 From: Daniel Vetter To: jeffy Cc: linux-kernel@vger.kernel.org, briannorris@chromium.org, dianders@chromium.org, tfiga@chromium.org, dri-devel@lists.freedesktop.org, zyw@rock-chips.com, Daniel Vetter Subject: Re: [PATCH v5 12/12] drm/drm_ioctl.c: Break ioctl when drm device not registered Message-ID: <20170407183429.pcojsp63nlsaljdc@phenom.ffwll.local> Mail-Followup-To: jeffy , linux-kernel@vger.kernel.org, briannorris@chromium.org, dianders@chromium.org, tfiga@chromium.org, dri-devel@lists.freedesktop.org, zyw@rock-chips.com, Daniel Vetter References: <1491481885-13775-1-git-send-email-jeffy.chen@rock-chips.com> <1491481885-13775-13-git-send-email-jeffy.chen@rock-chips.com> <20170407071659.hwf5f7jf2bjjdata@phenom.ffwll.local> <58E75AEB.6070700@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <58E75AEB.6070700@rock-chips.com> X-Operating-System: Linux phenom 4.9.0-2-amd64 User-Agent: NeoMutt/20170306 (1.8.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1853 Lines: 53 On Fri, Apr 07, 2017 at 05:24:59PM +0800, jeffy wrote: > Hi Daniel, > > On 04/07/2017 03:16 PM, Daniel Vetter wrote: > > On Thu, Apr 06, 2017 at 08:31:25PM +0800, Jeffy Chen wrote: > > > After unbinding drm, the user space may still owns the drm dev fd, > > > and may still be able to call drm ioctl. > > > > > > Add a sanity check here to prevent that from happening. > > > > > > Signed-off-by: Jeffy Chen > > > --- > > > > > > Changes in v5: None > > > Changes in v4: None > > > Changes in v3: None > > > Changes in v2: None > > > > > > drivers/gpu/drm/drm_ioctl.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c > > > index 7d6deaa..15beb11 100644 > > > --- a/drivers/gpu/drm/drm_ioctl.c > > > +++ b/drivers/gpu/drm/drm_ioctl.c > > > @@ -674,7 +674,7 @@ long drm_ioctl(struct file *filp, > > > > > > dev = file_priv->minor->dev; > > > > > > - if (drm_device_is_unplugged(dev)) > > > + if (drm_device_is_unplugged(dev) || !dev->registered) > > > > Shouldn't we instead automatically unplug the device in > > drm_dev_unregister, instead of sprinkling tons of drm_device_is_unplugged > > || !registered all over the place? > > > it looks like the drm_unplug_dev would call drm_dev_unregister... > maybe we can: > 1/ replace the dev_unplug_dev in udl_drv.c to drm_dev_unregister > 2/ call dev_unplug_dev in drm_dev_unregister, and remove drm_dev_unregister > in dev_unplug_dev > 3/ add a drm_plug_dev or drm_device_set_plugged, and call it in > drm_dev_register Yeah, sounds like a reasonable plan. I didn't review the full implications of this because Fri evening :-) So pls double-check before you rewrite the world ... Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch