powerpc/pseries: handle nodes without '/'

In case we have node without '/' strrchr() returns NULL which might lead to
crash. Replace strrchr() by kbasename() and modify condition to avoid such
behaviour.

Suggested-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
index 8c6b05a..4417afe 100644 (file)
--- a/arch/powerpc/platforms/pseries/of_helpers.c
+++ b/arch/powerpc/platforms/pseries/of_helpers.c
@@ -17,14 +17,14 @@ struct device_node *pseries_of_derive_parent(const char *path)
 {
        struct device_node *parent;
        char *parent_path = "/";
-       size_t parent_path_len = strrchr(path, '/') - path + 1;
+       const char *tail = kbasename(path);
 
        /* reject if path is "/" */
        if (!strcmp(path, "/"))
                return ERR_PTR(-EINVAL);
 
-       if (strrchr(path, '/') != path) {
-               parent_path = kstrndup(path, parent_path_len, GFP_KERNEL);
+       if (tail > path + 1) {
+               parent_path = kstrndup(path, tail - path, GFP_KERNEL);
                if (!parent_path)
                        return ERR_PTR(-ENOMEM);
        }