[PATCH] of: fdt: add missing allocation-failure check

[Johan Hovold]

The memory allocator passed to __unflatten_device_tree() (e.g. a wrapped
kzalloc) can fail so add the missing sanity check to avoid dereferencing
a NULL pointer.

Fixes: fe14042358fa ("of/flattree: Refactor unflatten_device_tree and add fdt_unflatten_tree")
Cc: stable <stable@xxxxxxxxxxxxxxx>     # 2.6.38
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
 drivers/of/fdt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 3080d9dd031d..43bd69dceabf 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -507,6 +507,9 @@ void *__unflatten_device_tree(const void *blob,
 
 	/* Allocate memory for the expanded device tree */
 	mem = dt_alloc(size + 4, __alignof__(struct device_node));
+	if (!mem)
+		return NULL;
+
 	memset(mem, 0, size);
 
 	*(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
-- 
2.13.0