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From:   Changbin Du <changbin.du@gmail.com>
To:     Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Changbin Du <changbin.du@gmail.com>
Subject: [PATCH] of/fdt: Check dtb pointer first in unflatten_device_tree
Date:   Wed, 24 Mar 2021 23:04:25 +0800
Message-Id: <20210324150425.20688-1-changbin.du@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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.du@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