linux-kernel - Re: [BUG] drm/radeon: locking problems with page

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Message-ID: <1315906152.17617.24.camel@thor.local>
Date:	Tue, 13 Sep 2011 11:29:12 +0200
From:	Michel Dänzer <michel@...nzer.net>
To:	Witold Baryluk <baryluk@....if.uj.edu.pl>
Cc:	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [BUG] drm/radeon: locking problems with page_flip

On Die, 2011-09-13 at 05:49 +0200, Witold Baryluk wrote: 
> 
> I yeasterday discovered pretty nasty issue in radeon / drm code,
> and page_flip locking code on my ThinkPad T43.

Does the patch below fix the problem?


>From ed7cf809c4fb737fa486b24004ee47056bf0e797 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daenzer@....com>
Date: Thu, 8 Sep 2011 17:36:22 +0200
Subject: [PATCH] drm/radeon: Unreference GEM object outside of spinlock
 in page flip error path.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Should fix https://bugzilla.redhat.com/show_bug.cgi?id=726277 .

Signed-off-by: Michel Dänzer <michel.daenzer@....com>
---
 drivers/gpu/drm/radeon/radeon_display.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 6cc17fb..6adb3e5 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -473,8 +473,8 @@ pflip_cleanup:
 	spin_lock_irqsave(&dev->event_lock, flags);
 	radeon_crtc->unpin_work = NULL;
 unlock_free:
-	drm_gem_object_unreference_unlocked(old_radeon_fb->obj);
 	spin_unlock_irqrestore(&dev->event_lock, flags);
+	drm_gem_object_unreference_unlocked(old_radeon_fb->obj);
 	radeon_fence_unref(&work->fence);
 	kfree(work);
 
-- 
1.7.5.4

-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer
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