From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37130 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754229AbdGYTZp (ORCPT ); Tue, 25 Jul 2017 15:25:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chris Wilson , Joonas Lahtinen , Daniel Vetter , Tvrtko Ursulin , Jani Nikula Subject: [PATCH 4.12 192/196] drm/i915/fbdev: Check for existence of ifbdev->vma before operations Date: Tue, 25 Jul 2017 12:23:11 -0700 Message-Id: <20170725192055.328204206@linuxfoundation.org> In-Reply-To: <20170725192046.422343510@linuxfoundation.org> References: <20170725192046.422343510@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Wilson commit 7581d5ca2bb269cfc2ce2d0cb489aac513167f6b upstream. Commit fabef825626d ("drm/i915: Drop struct_mutex around frontbuffer flushes") adds a dependency to ifbdev->vma when flushing the framebufer, but the checks are only against the existence of the ifbdev->fb and not against ifbdev->vma. This leaves a window of opportunity where we may try to operate on the fbdev prior to it being probed (thanks to asynchronous booting). Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101534 Fixes: fabef825626d ("drm/i915: Drop struct_mutex around frontbuffer flushes") Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Cc: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20170622160211.783-1-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin (cherry picked from commit 15727ed0d944ce1dec8b9e1082dd3df29a0fdf44) Signed-off-by: Jani Nikula Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/intel_fbdev.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/i915/intel_fbdev.c +++ b/drivers/gpu/drm/i915/intel_fbdev.c @@ -535,13 +535,14 @@ static void intel_fbdev_destroy(struct i drm_fb_helper_fini(&ifbdev->helper); - if (ifbdev->fb) { + if (ifbdev->vma) { mutex_lock(&ifbdev->helper.dev->struct_mutex); intel_unpin_fb_vma(ifbdev->vma); mutex_unlock(&ifbdev->helper.dev->struct_mutex); + } + if (ifbdev->fb) drm_framebuffer_remove(&ifbdev->fb->base); - } kfree(ifbdev); } @@ -765,7 +766,7 @@ void intel_fbdev_set_suspend(struct drm_ struct intel_fbdev *ifbdev = dev_priv->fbdev; struct fb_info *info; - if (!ifbdev || !ifbdev->fb) + if (!ifbdev || !ifbdev->vma) return; info = ifbdev->helper.fbdev; @@ -812,7 +813,7 @@ void intel_fbdev_output_poll_changed(str { struct intel_fbdev *ifbdev = to_i915(dev)->fbdev; - if (ifbdev && ifbdev->fb) + if (ifbdev && ifbdev->vma) drm_fb_helper_hotplug_event(&ifbdev->helper); } @@ -824,7 +825,7 @@ void intel_fbdev_restore_mode(struct drm return; intel_fbdev_sync(ifbdev); - if (!ifbdev->fb) + if (!ifbdev->vma) return; if (drm_fb_helper_restore_fbdev_mode_unlocked(&ifbdev->helper) == 0)