[PATCH] of/fdt: Check dtb pointer first in unflatten_device_tree

[Changbin Du]

The setup_arch() would invoke unflatten_device_tree() even no
valid fdt found. So we'd better check it first and return early.

Signed-off-by: Changbin Du <changbin...@gmail.com>
---
 drivers/of/fdt.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index dcc1dd96911a..05d439d63bc5 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1225,6 +1225,11 @@ bool __init early_init_dt_scan(void *params)
  */
 void __init unflatten_device_tree(void)
 {
+       if (!initial_boot_params) {
+               pr_warn("No valid device tree found, continuing without\n");
+               return;
+       }
+
        __unflatten_device_tree(initial_boot_params, NULL, &of_root,
                                early_init_dt_alloc_memory_arch, false);
 
-- 
2.30.2