clk: fix new_parent dereference before null check

Commit 71472c0 (clk: add support for clock reparent on set_rate) added a dereference of the new_parent pointer in clk_reparent(), but as detected by smatch clk_reparent() later checks whether new_parent is NULL.

The dereference was in order to clear the new parent's new_child pointer to avoid duplicate POST_RATE_CHANGE notifications, so clearly isn't necessary if the new parent is NULL, so move it inside the "if (new_parent)" block.

Reported-by Dan Carpenter <[email protected]>

Signed-off-by James Hogan <[email protected]>

Cc Mike Turquette <[email protected]>

Cc linux-arm-kernel at lists.infradead.org

---
 drivers/clk/clk.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

drivers/clk/clk.c +7 -6

index 2db08c0..02e75d4 100644
@@ -1108,16 +1108,17 @@ static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
 
 static void clk_reparent(struct clk *clk, struct clk *new_parent)
 {
-       /* avoid duplicate POST_RATE_CHANGE notifications */
-       if (new_parent->new_child == clk)
-               new_parent->new_child = NULL;
-
        hlist_del(&clk->child_node);
 
-       if (new_parent)
+       if (new_parent) {
+               /* avoid duplicate POST_RATE_CHANGE notifications */
+               if (new_parent->new_child == clk)
+                       new_parent->new_child = NULL;
+
                hlist_add_head(&clk->child_node, &new_parent->children);
-       else
+       } else {
                hlist_add_head(&clk->child_node, &clk_orphan_list);
+       }
 
        clk->parent = new_parent;
 }

Signature · 1 line

1.8.1.2