From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754357AbdCBIvm (ORCPT ); Thu, 2 Mar 2017 03:51:42 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:33856 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753937AbdCBIvk (ORCPT ); Thu, 2 Mar 2017 03:51:40 -0500 Date: Thu, 2 Mar 2017 09:14:56 +0100 From: Boris Brezillon To: Eric Anholt Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2 RESEND] drm/vc4: Fix OOPSes from trying to cache a partially constructed BO. Message-ID: <20170302091456.7a46b592@bbrezillon> In-Reply-To: <20170301185602.6873-2-eric@anholt.net> References: <20170301185602.6873-1-eric@anholt.net> <20170301185602.6873-2-eric@anholt.net> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Mar 2017 10:56:02 -0800 Eric Anholt wrote: > If a CMA allocation failed, the partially constructed BO would be > unreferenced through the normal path, and we might choose to put it in > the BO cache. If we then reused it before it expired from the cache, > the kernel would OOPS. > > Signed-off-by: Eric Anholt > Fixes: c826a6e10644 ("drm/vc4: Add a BO cache.") Reviewed-by: Boris Brezillon > --- > drivers/gpu/drm/vc4/vc4_bo.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c > index e5c7aa935b4b..af29432a6471 100644 > --- a/drivers/gpu/drm/vc4/vc4_bo.c > +++ b/drivers/gpu/drm/vc4/vc4_bo.c > @@ -317,6 +317,14 @@ void vc4_free_object(struct drm_gem_object *gem_bo) > goto out; > } > > + /* If this object was partially constructed but CMA allocation > + * had failed, just free it. > + */ > + if (!bo->base.vaddr) { > + vc4_bo_destroy(bo); > + goto out; > + } > + > cache_list = vc4_get_cache_list_for_size(dev, gem_bo->size); > if (!cache_list) { > vc4_bo_destroy(bo);