of: Add check to of_scan_flat_dt() before accessing initial_boot_params
authorTobias Wolf <dev-NTEO@vplace.de>
Wed, 23 Nov 2016 09:40:07 +0000 (10:40 +0100)
committerRalf Baechle <ralf@linux-mips.org>
Tue, 3 Jan 2017 15:34:43 +0000 (16:34 +0100)
An empty __dtb_start to __dtb_end section might result in
initial_boot_params being null for arch/mips/ralink. This showed that the
boot process hangs indefinitely in of_scan_flat_dt().

Signed-off-by: Tobias Wolf <dev-NTEO@vplace.de>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14605/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
drivers/of/fdt.c

index c9b5cac03b361c980a20c888635bbb52093aa573..82967b07f7be7d094870c4bef172bdb9d29adad0 100644 (file)
@@ -738,9 +738,12 @@ int __init of_scan_flat_dt(int (*it)(unsigned long node,
        const char *pathp;
        int offset, rc = 0, depth = -1;
 
-        for (offset = fdt_next_node(blob, -1, &depth);
-             offset >= 0 && depth >= 0 && !rc;
-             offset = fdt_next_node(blob, offset, &depth)) {
+       if (!blob)
+               return 0;
+
+       for (offset = fdt_next_node(blob, -1, &depth);
+            offset >= 0 && depth >= 0 && !rc;
+            offset = fdt_next_node(blob, offset, &depth)) {
 
                pathp = fdt_get_name(blob, offset, NULL);
                if (*pathp == '/')