path: root/drivers
diff options
authorMarek Vasut <marex@denx.de>2017-01-28 18:01:57 +0100
committerDave Airlie <airlied@redhat.com>2017-03-10 11:10:59 +1000
commit7ad7a5acfb96215216f46b9848bd2d341663358f (patch)
tree1f4beba082b8db1563e96805d378b2abb5670769 /drivers
parent53990e416bb7adaa59d045f325a47f31a11b75ee (diff)
drm: mxsfb: Fix crash when provided invalid DT bindings
The mxsfb driver will crash if the mxsfb DT node has a subnode, but the content of the subnode is not of-graph binding with an endpoint linking to panel. The crash was triggered by providing old-style panel bindings to the mxsfb driver instead of the new of-graph ones. The problem happens in mxsfb_create_output(), which is invoked from mxsfb_load(). The mxsfb_create_output() iterates over all mxsfb DT subnode endpoints and tries to bind a panel on each endpoint. If there is any problem binding the panel, that is, mxsfb->panel == NULL, this function will return an error code, otherwise success 0 is returned. If the subnodes do not specify of-graph binding with an endpoint, the iteration over endpoints in mxsfb_create_output() will have zero cycles and the function will immediatelly return 0, but the mxsfb->panel will remain NULL. This is propagated back into the mxsfb_load(), which does not detect any problem and expects that the mxsfb->panel is valid, thus calls mxsfb_panel_attach(). But since mxsfb->panel == NULL, mxsfb_panel_attach() is called with first argument NULL and this crashes the kernel. This patch fixes the problem by explicitly checking for valid mxsfb->panel at the end of the iteration in mxsfb_create_output(). Signed-off-by: Marek Vasut <marex@denx.de> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dave Airlie <airlied@redhat.com> Cc: Stefan Agner <stefan@agner.ch> Cc: Breno Matheus Lima <brenomatheus@gmail.com> Tested-by: Breno Lima <breno.lima@nxp.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers')
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_out.c b/drivers/gpu/drm/mxsfb/mxsfb_out.c
index fa8d17399407..b8e81422d4e2 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_out.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_out.c
@@ -112,6 +112,7 @@ static int mxsfb_attach_endpoint(struct drm_device *drm,
int mxsfb_create_output(struct drm_device *drm)
+ struct mxsfb_drm_private *mxsfb = drm->dev_private;
struct device_node *ep_np = NULL;
struct of_endpoint ep;
int ret;
@@ -127,5 +128,8 @@ int mxsfb_create_output(struct drm_device *drm)
+ if (!mxsfb->panel)
+ return -EPROBE_DEFER;
return 0;

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