Revert "net/ipv6: fix metrics leak"

This reverts commit df18b50448fab1dff093731dfd0e25e77e1afcd1.

This change causes other problems and use-after-free situations as
found by syzbot.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 14 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 211a2d437b56..d212738e9d10 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -167,22 +167,11 @@ struct fib6_info *fib6_info_alloc(gfp_t gfp_flags)
         return f6i;
 }
 
-static void fib6_metrics_release(struct fib6_info *f6i)
-{
-        struct dst_metrics *m;
-
-        if (!f6i)
-                return;
-
-        m = f6i->fib6_metrics;
-        if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
-                kfree(m);
-}
-
 void fib6_info_destroy_rcu(struct rcu_head *head)
 {
         struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
         struct rt6_exception_bucket *bucket;
+        struct dst_metrics *m;
 
         WARN_ON(f6i->fib6_node);
 
@@ -212,7 +201,9 @@ void fib6_info_destroy_rcu(struct rcu_head *head)
         if (f6i->fib6_nh.nh_dev)
                 dev_put(f6i->fib6_nh.nh_dev);
 
-        fib6_metrics_release(f6i);
+        m = f6i->fib6_metrics;
+        if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
+                kfree(m);
 
         kfree(f6i);
 }
@@ -896,7 +887,6 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i,
 
                         from = rcu_dereference_protected(pcpu_rt->from,
                                              lockdep_is_held(&table->tb6_lock));
-                        fib6_metrics_release(from);
                         rcu_assign_pointer(pcpu_rt->from, NULL);
                         fib6_info_release(from);
                 }