Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753840AbdFGXRc (ORCPT ); Wed, 7 Jun 2017 19:17:32 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:50848 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753592AbdFGXGI (ORCPT ); Wed, 7 Jun 2017 19:06:08 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Andrey Ryabinin , Daniel Vetter , Jani Nikula , Willy Tarreau Subject: [PATCH 3.10 116/250] drm/i915: fix use-after-free in page_flip_completed() Date: Thu, 8 Jun 2017 00:58:22 +0200 Message-Id: <1496876436-32402-117-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1496876436-32402-1-git-send-email-w@1wt.eu> References: <1496876436-32402-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2240 Lines: 63 From: Andrey Ryabinin commit 5351fbb1bf1413f6024892093528280769ca852f upstream. page_flip_completed() dereferences 'work' variable after executing queue_work(). This is not safe as the 'work' item might be already freed by queued work: BUG: KASAN: use-after-free in page_flip_completed+0x3ff/0x490 at addr ffff8803dc010f90 Call Trace: __asan_report_load8_noabort+0x59/0x80 page_flip_completed+0x3ff/0x490 intel_finish_page_flip_mmio+0xe3/0x130 intel_pipe_handle_vblank+0x2d/0x40 gen8_irq_handler+0x4a7/0xed0 __handle_irq_event_percpu+0xf6/0x860 handle_irq_event_percpu+0x6b/0x160 handle_irq_event+0xc7/0x1b0 handle_edge_irq+0x1f4/0xa50 handle_irq+0x41/0x70 do_IRQ+0x9a/0x200 common_interrupt+0x89/0x89 Freed: kfree+0x113/0x4d0 intel_unpin_work_fn+0x29a/0x3b0 process_one_work+0x79e/0x1b70 worker_thread+0x611/0x1460 kthread+0x241/0x3a0 ret_from_fork+0x27/0x40 Move queue_work() after trace_i915_flip_complete() to fix this. Fixes: e5510fac98a7 ("drm/i915: add tracepoints for flip requests & completions") Signed-off-by: Andrey Ryabinin Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20170126143211.24013-1-aryabinin@virtuozzo.com Signed-off-by: Jani Nikula Signed-off-by: Andrey Ryabinin Signed-off-by: Willy Tarreau --- drivers/gpu/drm/i915/intel_display.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 8814b0d..a7dbdec 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7052,9 +7052,9 @@ static void do_intel_finish_page_flip(struct drm_device *dev, wake_up_all(&dev_priv->pending_flip_queue); - queue_work(dev_priv->wq, &work->work); - trace_i915_flip_complete(intel_crtc->plane, work->pending_flip_obj); + + queue_work(dev_priv->wq, &work->work); } void intel_finish_page_flip(struct drm_device *dev, int pipe) -- 2.8.0.rc2.1.gbe9624a