linux-kernel - [PATCH 3.10 180/319] drm: Reject page_flip for !DRIVER

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Message-Id: <1486322541-8206-81-git-send-email-w@1wt.eu>
Date:   Sun,  5 Feb 2017 20:20:02 +0100
From:   Willy Tarreau <w@....eu>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        linux@...ck-us.net
Cc:     Daniel Vetter <daniel.vetter@...ll.ch>,
        Alexander Potapenko <glider@...gle.com>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Dave Airlie <airlied@...hat.com>, Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 180/319] drm: Reject page_flip for !DRIVER_MODESET

From: Daniel Vetter <daniel.vetter@...ll.ch>

commit 6f00975c619064a18c23fd3aced325ae165a73b9 upstream.

Somehow this one slipped through, which means drivers without modeset
support can be oopsed (since those also don't call
drm_mode_config_init, which means the crtc lookup will chase an
uninitalized idr).

Reported-by: Alexander Potapenko <glider@...gle.com>
Cc: Alexander Potapenko <glider@...gle.com>
Signed-off-by: Daniel Vetter <daniel.vetter@...el.com>
Reviewed-by: Chris Wilson <chris@...is-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@...hat.com>
Signed-off-by: Willy Tarreau <w@....eu>
---
 drivers/gpu/drm/drm_crtc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index c24c356..121680f 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3422,6 +3422,9 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 	int hdisplay, vdisplay;
 	int ret = -EINVAL;
 
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
 	if (page_flip->flags & ~DRM_MODE_PAGE_FLIP_FLAGS ||
 	    page_flip->reserved != 0)
 		return -EINVAL;
-- 
2.8.0.rc2.1.gbe9624a