Re: [syzbot] [net?] [s390?] KASAN: slab-use-after-free Read in netdev_walk_all_lower_dev

[Hillf Danton]

On Fri, 06 Dec 2024 07:59:25 -0800
> syzbot found the following issue on:
> 
> HEAD commit:    896d8946da97 Merge tag 'net-6.13-rc2' of git://git.kernel...
> git tree:       net
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10de5330580000

#syz test

--- x/net/smc/smc_core.c
+++ y/net/smc/smc_core.c
@@ -1896,7 +1896,9 @@ int smc_vlan_by_tcpsk(struct socket *clc
 
 	priv.data = (void *)&ini->vlan_id;
 	rtnl_lock();
+	rcu_read_lock();
 	netdev_walk_all_lower_dev(ndev, smc_vlan_by_tcpsk_walk, &priv);
+	rcu_read_unlock();
 	rtnl_unlock();
 
 out_rel:
--