[PATCH] reset: Fix potential use-after-free in __of_reset_control_get()

[Geert Uytterhoeven]

Calling of_node_put() decreases the reference count of a device tree
object, and may free some data.

However, the of_phandle_args structure embedding it is passed to
reset_controller_dev.of_xlate() after that, so it may still be accessed.

Move the call to of_node_put() down to fix this.

Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be>
---
 drivers/reset/core.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 225e34c56b94a2e3..bc9df10d31b4bae1 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -496,27 +496,28 @@ struct reset_control *__of_reset_control_get(struct 
device_node *node,
                        break;
                }
        }
-       of_node_put(args.np);
 
        if (!rcdev) {
-               mutex_unlock(&reset_list_mutex);
-               return ERR_PTR(-EPROBE_DEFER);
+               rstc = ERR_PTR(-EPROBE_DEFER);
+               goto out;
        }
 
        if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
-               mutex_unlock(&reset_list_mutex);
-               return ERR_PTR(-EINVAL);
+               rstc = ERR_PTR(-EINVAL);
+               goto out;
        }
 
        rstc_id = rcdev->of_xlate(rcdev, &args);
        if (rstc_id < 0) {
-               mutex_unlock(&reset_list_mutex);
-               return ERR_PTR(rstc_id);
+               rstc = ERR_PTR(rstc_id);
+               goto out;
        }
 
        /* reset_list_mutex also protects the rcdev's reset_control list */
        rstc = __reset_control_get_internal(rcdev, rstc_id, shared);
 
+out:
+       of_node_put(args.np);
        mutex_unlock(&reset_list_mutex);
 
        return rstc;
-- 
2.17.1