[POWERPC] Check for the root node in of_detach_node()

It's not sensible to call of_detach_node() on the root node,
but we should check for it just to be safe.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 6f32bebd8a9b..cc9632c7149e 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1432,6 +1432,8 @@ void of_detach_node(const struct device_node *np)
         write_lock(&devtree_lock);
 
         parent = np->parent;
+        if (!parent)
+                goto out_unlock;
 
         if (allnodes == np)
                 allnodes = np->allnext;
@@ -1455,6 +1457,7 @@ void of_detach_node(const struct device_node *np)
                 prevsib->sibling = np->sibling;
         }
 
+out_unlock:
         write_unlock(&devtree_lock);
 }