On Wed, Mar 05, 2025 at 10:02:34PM +0800, Dong Chenchen wrote: > WARNING: CPU: 0 PID: 6558 at net/core/sock_map.c:1703 sock_map_close+0x3c4/0x480 > Modules linked in: > CPU: 0 UID: 0 PID: 6558 Comm: syz-executor.14 Not tainted 6.14.0-rc5+ #238 > RIP: 0010:sock_map_close+0x3c4/0x480 > Call Trace: > <TASK> > inet_release+0x144/0x280 > __sock_release+0xb8/0x270 > sock_close+0x1e/0x30 > __fput+0x3c6/0xb30 > __fput_sync+0x7b/0x90 > __x64_sys_close+0x90/0x120 > do_syscall_64+0x5d/0x170 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > The root cause is: > sock_hash_update_common > sock_map_unref > sock_map_del_link > psock->psock_update_sk_prot(sk, psock, false); > //false won't restore proto > sk_psock_put > rcu_assign_sk_user_data(sk, NULL); > inet_release > sk->sk_prot->close > sock_map_close > WARN(sk->sk_prot->close == sock_map_close) > > When psock is removed from sockmap, sock_map_del_link() still set > sk->sk_prot to bpf proto instead of restore it (for incorrect restore > value). sock release will triger warning of sock_map_close() for > recurse after psock drop. But sk_psock_drop() restores it with sk_psock_restore_proto() after the psock reference count goes to zero. So how could the above happen? By the way, it would be perfect if you could add a test case for it together with this patch (a followup patch is fine too). Thanks!
