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| author |   Marek Vasut <marex@denx.de> | 2017-01-28 18:01:57 +0100 |
|---|---|---|
| committer |   Dave Airlie <airlied@redhat.com> | 2017-03-10 11:10:59 +1000 |
| commit | 7ad7a5acfb96215216f46b9848bd2d341663358f (patch) | |
| tree | 1f4beba082b8db1563e96805d378b2abb5670769 /drivers/gpu | |
| parent | drm: mxsfb: fix pixel clock polarity (diff) | |
| download | linux-dev-7ad7a5acfb96215216f46b9848bd2d341663358f.tar.xz linux-dev-7ad7a5acfb96215216f46b9848bd2d341663358f.zip | |
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/gpu')
| -rw-r--r-- | drivers/gpu/drm/mxsfb/mxsfb_out.c | 4 |
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; } |