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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>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.