[POWERPC] CHRP: Fix possible NULL pointer dereference

This fixes a possible NULL pointer dereference inside of strncmp() if
of_get_property() fails.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 9 insertions, 4 deletions

diff --git a/arch/powerpc/platforms/chrp/setup.c b/arch/powerpc/platforms/chrp/setup.c
index 59306261f5b2..42a21bab76c8 100644
--- a/arch/powerpc/platforms/chrp/setup.c
+++ b/arch/powerpc/platforms/chrp/setup.c
@@ -115,7 +115,7 @@ void chrp_show_cpuinfo(struct seq_file *m)
         seq_printf(m, "machine\t\t: CHRP %s\n", model);
 
         /* longtrail (goldengate) stuff */
-        if (!strncmp(model, "IBM,LongTrail", 13)) {
+        if (model && !strncmp(model, "IBM,LongTrail", 13)) {
                 /* VLSI VAS96011/12 `Golden Gate 2' */
                 /* Memory banks */
                 sdramen = (in_le32(gg2_pci_config_base + GG2_PCI_DRAM_CTRL)
@@ -203,15 +203,20 @@ static void __init sio_fixup_irq(const char *name, u8 device, u8 level,
 static void __init sio_init(void)
 {
         struct device_node *root;
+        const char *model;
 
-        if ((root = of_find_node_by_path("/")) &&
-            !strncmp(of_get_property(root, "model", NULL),
-                        "IBM,LongTrail", 13)) {
+        root = of_find_node_by_path("/");
+        if (!root)
+                return;
+
+        model = of_get_property(root, "model", NULL);
+        if (model && !strncmp(model, "IBM,LongTrail", 13)) {
                 /* logical device 0 (KBC/Keyboard) */
                 sio_fixup_irq("keyboard", 0, 1, 2);
                 /* select logical device 1 (KBC/Mouse) */
                 sio_fixup_irq("mouse", 1, 12, 2);
         }
+
         of_node_put(root);
 }