Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755455AbdDEQ3w (ORCPT ); Wed, 5 Apr 2017 12:29:52 -0400 Received: from mail-qt0-f179.google.com ([209.85.216.179]:36091 "EHLO mail-qt0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752981AbdDEQ2n (ORCPT ); Wed, 5 Apr 2017 12:28:43 -0400 Date: Wed, 5 Apr 2017 12:28:40 -0400 From: Sean Paul To: Jeffy Chen Cc: linux-kernel@vger.kernel.org, briannorris@chromium.org, dianders@chromium.org, tfiga@chromium.org, seanpaul@chromium.org, zyw@rock-chips.com, mark.yao@rock-chips.com, Heiko Stuebner , dri-devel@lists.freedesktop.org, linux-rockchip@lists.infradead.org, David Airlie , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3 8/9] drm/rockchip: gem: Don't alloc/free gem buf when dev_private is invalid Message-ID: <20170405162839.k6q4b3tpt6t2s3zm@art_vandelay> References: <1491380967-28570-1-git-send-email-jeffy.chen@rock-chips.com> <1491380967-28570-9-git-send-email-jeffy.chen@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1491380967-28570-9-git-send-email-jeffy.chen@rock-chips.com> User-Agent: NeoMutt/20170306-66-6ddb52-dirty (1.8.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1641 Lines: 57 On Wed, Apr 05, 2017 at 04:29:26PM +0800, Jeffy Chen wrote: > After unbinding drm, the userspace may still has a chance to access > gem buf. > > Add a sanity check for a NULL dev_private to prevent that from > happening. I still don't understand how this is happening. You're saying that these hooks can be called after rockchip_drm_unbind() has finished? Sean > > Signed-off-by: Jeffy Chen > --- > > Changes in v3: > Address Daniel Vetter 's comments. > Update commit message. > > Changes in v2: None > > drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c > index df9e570..205a3dc 100644 > --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c > @@ -184,6 +184,9 @@ static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj, > struct drm_device *drm = obj->dev; > struct rockchip_drm_private *private = drm->dev_private; > > + if (!private) > + return -ENODEV; > + > if (private->domain) > return rockchip_gem_alloc_iommu(rk_obj, alloc_kmap); > else > @@ -208,6 +211,11 @@ static void rockchip_gem_free_dma(struct rockchip_gem_object *rk_obj) > > static void rockchip_gem_free_buf(struct rockchip_gem_object *rk_obj) > { > + struct drm_device *drm = rk_obj->base.dev; > + > + if (!drm->dev_private) > + return; > + > if (rk_obj->pages) > rockchip_gem_free_iommu(rk_obj); > else > -- > 2.1.4 > -- Sean Paul, Software Engineer, Google / Chromium OS