tree 9327896dc5df8d709029f8ded5ee2e0042e5e5a8
parent ba85edbe0d39710dc74a2a9c6f90929b5722a53b
author Guenter Roeck <linux@roeck-us.net> 1449360833 -0800
committer Rob Herring <robh@kernel.org> 1449589842 -0600

of/fdt: Add mutex protection for calls to __unflatten_device_tree()

__unflatten_device_tree() calls unflatten_dt_node(), which declares
a static variable. It is therefore not reentrant.

One of the callers of __unflatten_device_tree(), unflatten_device_tree(),
is only called once during early initialization and does not need to be
protected. The other caller, of_fdt_unflatten_tree(), can be called at
any time, possibly multiple times in parallel. This can happen, for
example, if multiple devicetree overlays have to be loaded and installed.

Without this protection, errors such as the following may be seen.

kernel: End of tree marker overwritten: e6a3a458
kernel: find_target_node:
	Failed to find target-indirect node at /fragment@0
kernel: __of_overlay_create: of_build_overlay_info() failed for tree@/

Add a mutex to of_fdt_unflatten_tree() to make the call reentrant.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: Rob Herring <robh@kernel.org>