From patchwork Wed Jan 27 20:34:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 574321 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 7E9FE140B8C; Thu, 28 Jan 2016 07:48:12 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aOX0b-0001Je-6l; Wed, 27 Jan 2016 20:48:09 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aOWsJ-0006rx-7v for kernel-team@lists.ubuntu.com; Wed, 27 Jan 2016 20:39:35 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aOWsI-0003gi-N0; Wed, 27 Jan 2016 20:39:34 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1aOWsF-0004xb-VH; Wed, 27 Jan 2016 12:39:31 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 4.2.y-ckt 192/268] drm/i915: On fb alloc failure, unref gem object where it gets refed Date: Wed, 27 Jan 2016 12:34:13 -0800 Message-Id: <1453926929-17663-193-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1453926929-17663-1-git-send-email-kamal@canonical.com> References: <1453926929-17663-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 X-Extended-Stable: 4.2 Cc: Jani Nikula , Lukas Wunner , Kamal Mostafa , Chris Wilson , Tvrtko Ursulin X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 4.2.8-ckt3 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Lukas Wunner commit dcb1394e74e32e33856e877bca1a0e88c78323d8 upstream. Currently when allocating a framebuffer fails, the gem object gets unrefed at the bottom of the call stack in __intel_framebuffer_create, not where it gets refed, which is in intel_framebuffer_create_for_mode (via i915_gem_alloc_object) and in intel_user_framebuffer_create (via drm_gem_object_lookup). This invites mistakes: __intel_framebuffer_create is also called from intelfb_alloc, and as discovered by Tvrtko Ursulin, a double unref was introduced there with a8bb6818270c ("drm/i915: Fix error path leak in fbdev fb allocation"). As suggested by Ville Syrjälä, fix the double unref and improve code clarity by moving the unref away from __intel_framebuffer_create to where the gem object gets refed. Based on Tvrtko Ursulin's original v2. v3: On fb alloc failure, unref gem object where it gets refed, fix double unref in separate commit (Ville Syrjälä) v4: Lock struct_mutex on unref (Chris Wilson) v5: Rebase on drm-intel-nightly 2015y-09m-01d-09h-06m-08s UTC, rephrase commit message (Jani Nicula) Tested-by: Pierre Moreau [MBP 5,3 2009 nvidia MCP79 + G96 pre-retina] Tested-by: Paul Hordiienko [MBP 6,2 2010 intel ILK + nvidia GT216 pre-retina] Tested-by: William Brown [MBP 8,2 2011 intel SNB + amd turks pre-retina] Tested-by: Lukas Wunner [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina] Tested-by: Bruno Bierbaumer [MBP 11,3 2013 intel HSW + nvidia GK107 retina] Fixes: a8bb6818270c ("drm/i915: Fix error path leak in fbdev fb allocation") Cc: Tvrtko Ursulin Cc: Chris Wilson Signed-off-by: Lukas Wunner Reviewed-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/2161c5062ef5d6458f8ae14d924a26d4d1dba317.1446892879.git.lukas@wunner.de Signed-off-by: Jani Nikula [ kamal: backport to 4.2-stable: context ] Signed-off-by: Kamal Mostafa --- drivers/gpu/drm/i915/intel_display.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 05bf98d..8bd37dd 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -9817,20 +9817,17 @@ __intel_framebuffer_create(struct drm_device *dev, int ret; intel_fb = kzalloc(sizeof(*intel_fb), GFP_KERNEL); - if (!intel_fb) { - drm_gem_object_unreference(&obj->base); + if (!intel_fb) return ERR_PTR(-ENOMEM); - } ret = intel_framebuffer_init(dev, intel_fb, mode_cmd, obj); if (ret) goto err; return &intel_fb->base; + err: - drm_gem_object_unreference(&obj->base); kfree(intel_fb); - return ERR_PTR(ret); } @@ -9870,6 +9867,7 @@ intel_framebuffer_create_for_mode(struct drm_device *dev, struct drm_display_mode *mode, int depth, int bpp) { + struct drm_framebuffer *fb; struct drm_i915_gem_object *obj; struct drm_mode_fb_cmd2 mode_cmd = { 0 }; @@ -9884,7 +9882,11 @@ intel_framebuffer_create_for_mode(struct drm_device *dev, bpp); mode_cmd.pixel_format = drm_mode_legacy_fb_format(bpp, depth); - return intel_framebuffer_create(dev, &mode_cmd, obj); + fb = intel_framebuffer_create(dev, &mode_cmd, obj); + if (IS_ERR(fb)) + drm_gem_object_unreference_unlocked(&obj->base); + + return fb; } static struct drm_framebuffer * @@ -14267,6 +14269,7 @@ intel_user_framebuffer_create(struct drm_device *dev, struct drm_file *filp, struct drm_mode_fb_cmd2 *user_mode_cmd) { + struct drm_framebuffer *fb; struct drm_i915_gem_object *obj; struct drm_mode_fb_cmd2 mode_cmd = *user_mode_cmd; @@ -14275,7 +14278,11 @@ intel_user_framebuffer_create(struct drm_device *dev, if (&obj->base == NULL) return ERR_PTR(-ENOENT); - return intel_framebuffer_create(dev, &mode_cmd, obj); + fb = intel_framebuffer_create(dev, &mode_cmd, obj); + if (IS_ERR(fb)) + drm_gem_object_unreference_unlocked(&obj->base); + + return fb; } #ifndef CONFIG_DRM_I915_FBDEV