Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754605AbdCTMHy (ORCPT ); Mon, 20 Mar 2017 08:07:54 -0400 Received: from mga03.intel.com ([134.134.136.65]:60341 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753775AbdCTMHw (ORCPT ); Mon, 20 Mar 2017 08:07:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,194,1486454400"; d="scan'208";a="238238579" Message-ID: <1490011236.3600.5.camel@linux.intel.com> Subject: Re: [PATCH 1/3] drm/i915: allocate mock file pointer dynamically From: Joonas Lahtinen To: Arnd Bergmann , Daniel Vetter , Jani Nikula , David Airlie Cc: Chris Wilson , Tvrtko Ursulin , Matthew Auld , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Date: Mon, 20 Mar 2017 14:00:36 +0200 In-Reply-To: <20170320094335.1266306-1-arnd@arndb.de> References: <20170320094335.1266306-1-arnd@arndb.de> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1986 Lines: 51 On ma, 2017-03-20 at 10:40 +0100, Arnd Bergmann wrote: > A struct file is a bit too large to put on the kernel stack in general > and triggers a warning for low settings of CONFIG_FRAME_WARN: > > drivers/gpu/drm/i915/selftests/mock_drm.c: In function 'mock_file': > drivers/gpu/drm/i915/selftests/mock_drm.c:46:1: error: the frame size of 1328 bytes is larger than 1280 bytes [-Werror=frame-larger-than=] > drivers/gpu/drm/i915/selftests/mock_drm.c: In function 'mock_file_free': > drivers/gpu/drm/i915/selftests/mock_drm.c:54:1: error: the frame size of 1312 bytes is larger than 1280 bytes [-Werror=frame-larger-than=] > > It's also slightly dangerous to leave a reference to a stack object > in the drm_file structure after leaving the stack frame. > This changes the code to just allocate the object dynamically > and release it when we are done with it. > > Fixes: 66d9cb5d805a ("drm/i915: Mock the GEM device for self-testing") > Signed-off-by: Arnd Bergmann > --- >  drivers/gpu/drm/i915/selftests/mock_drm.c | 12 +++++++----- >  1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/selftests/mock_drm.c b/drivers/gpu/drm/i915/selftests/mock_drm.c > index 113dec05c7dc..18514065c93d 100644 > --- a/drivers/gpu/drm/i915/selftests/mock_drm.c > +++ b/drivers/gpu/drm/i915/selftests/mock_drm.c > @@ -32,15 +32,15 @@ static inline struct inode fake_inode(struct drm_i915_private *i915) >  struct drm_file *mock_file(struct drm_i915_private *i915) >  { > >   struct inode inode = fake_inode(i915); > > - struct file filp = {}; > > + struct file *filp = kzalloc(sizeof(struct file), GFP_KERNEL); > >   struct drm_file *file; > >   int err; >   filp = kzalloc(sizeof(*filp), GFP_KERNEL); if (unlikely(!filp)) { err = -ENOMEM; goto err; } And appropriate onion teardown in case drm_open fails, so that we don't leak memory. Regards, Joonas -- Joonas Lahtinen Open Source Technology Center Intel Corporation