[PATCH 3.18 11/16] of: Add check to of_scan_flat_dt() before accessing initial_boot_params

Greg Kroah-Hartman
2017-06-27T13:03:17Z

From: Tobias Wolf <dev-NTEO@vplace.de>

commit 3ec754410cb3e931a6c4920b1a150f21a94a2bf4 upstream.

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>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/of/fdt.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -585,9 +585,12 @@ int __init of_scan_flat_dt(int (*it)(uns
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 == '/')