[PATH wpan v2] ieee802154: hwsim: Fix possible memory leaks

[Chen Aotian]

After replacing e->info, it is necessary to free the old einfo.

Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb")
Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Chen Aotian <chenaotian2@xxxxxxx>
---

V1 -> V2:
* Using rcu_replace_pointer() is better then rcu_dereference()
  and rcu_assign_pointer().

 drivers/net/ieee802154/mac802154_hwsim.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c
index 8445c2189..6ffcadb9d 100644
--- a/drivers/net/ieee802154/mac802154_hwsim.c
+++ b/drivers/net/ieee802154/mac802154_hwsim.c
@@ -685,7 +685,7 @@ static int hwsim_del_edge_nl(struct sk_buff *msg, struct genl_info *info)
 static int hwsim_set_edge_lqi(struct sk_buff *msg, struct genl_info *info)
 {
 	struct nlattr *edge_attrs[MAC802154_HWSIM_EDGE_ATTR_MAX + 1];
-	struct hwsim_edge_info *einfo;
+	struct hwsim_edge_info *einfo, *einfo_old;
 	struct hwsim_phy *phy_v0;
 	struct hwsim_edge *e;
 	u32 v0, v1;
@@ -723,8 +723,10 @@ static int hwsim_set_edge_lqi(struct sk_buff *msg, struct genl_info *info)
 	list_for_each_entry_rcu(e, &phy_v0->edges, list) {
 		if (e->endpoint->idx == v1) {
 			einfo->lqi = lqi;
-			rcu_assign_pointer(e->info, einfo);
+			einfo_old = rcu_replace_pointer(e->info, einfo,
+							lock_is_held(&hwsim_phys_lock));
 			rcu_read_unlock();
+			kfree_rcu(einfo_old, rcu);
 			mutex_unlock(&hwsim_phys_lock);
 			return 0;
 		}
-- 
2.25.1