[for-4.9,1/7] of: Add check to of_scan_flat_dt() before accessing initial_boot_params

Message ID 1498464091-26753-2-git-send-email-amit.pundir@linaro.org
State New
Headers show
Series
  • Stable commits picked up from lede project
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Commit Message

Amit Pundir June 26, 2017, 8:01 a.m.
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>

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

-- 
2.7.4

Patch

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 6a43fd3d0576..502f5547a1f2 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -741,9 +741,12 @@  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 == '/')