From 5399d52233c47905bbf97dcbaa2d7a9cc31670ba Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 29 Jan 2021 23:53:50 +0000 Subject: rxrpc: Fix deadlock around release of dst cached on udp tunnel AF_RXRPC sockets use UDP ports in encap mode. This causes socket and dst from an incoming packet to get stolen and attached to the UDP socket from whence it is leaked when that socket is closed. When a network namespace is removed, the wait for dst records to be cleaned up happens before the cleanup of the rxrpc and UDP socket, meaning that the wait never finishes. Fix this by moving the rxrpc (and, by dependence, the afs) private per-network namespace registrations to the device group rather than subsys group. This allows cached rxrpc local endpoints to be cleared and their UDP sockets closed before we try waiting for the dst records. The symptom is that lines looking like the following: unregister_netdevice: waiting for lo to become free get emitted at regular intervals after running something like the referenced syzbot test. Thanks to Vadim for tracking this down and work out the fix. Reported-by: syzbot+df400f2f24a1677cd7e0@syzkaller.appspotmail.com Reported-by: Vadim Fedorenko Fixes: 5271953cad31 ("rxrpc: Use the UDP encap_rcv hook") Signed-off-by: David Howells Acked-by: Vadim Fedorenko Link: https://lore.kernel.org/r/161196443016.3868642.5577440140646403533.stgit@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski --- net/rxrpc/af_rxrpc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'net/rxrpc') diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c index 0a2f4817ec6c..41671af6b33f 100644 --- a/net/rxrpc/af_rxrpc.c +++ b/net/rxrpc/af_rxrpc.c @@ -990,7 +990,7 @@ static int __init af_rxrpc_init(void) goto error_security; } - ret = register_pernet_subsys(&rxrpc_net_ops); + ret = register_pernet_device(&rxrpc_net_ops); if (ret) goto error_pernet; @@ -1035,7 +1035,7 @@ error_key_type: error_sock: proto_unregister(&rxrpc_proto); error_proto: - unregister_pernet_subsys(&rxrpc_net_ops); + unregister_pernet_device(&rxrpc_net_ops); error_pernet: rxrpc_exit_security(); error_security: @@ -1057,7 +1057,7 @@ static void __exit af_rxrpc_exit(void) unregister_key_type(&key_type_rxrpc); sock_unregister(PF_RXRPC); proto_unregister(&rxrpc_proto); - unregister_pernet_subsys(&rxrpc_net_ops); + unregister_pernet_device(&rxrpc_net_ops); ASSERTCMP(atomic_read(&rxrpc_n_tx_skbs), ==, 0); ASSERTCMP(atomic_read(&rxrpc_n_rx_skbs), ==, 0); -- cgit v1.2.3-59-g8ed1b