From fe94800184f22d4778628f1321dce5acb7513d84 Mon Sep 17 00:00:00 2001 From: Menglong Dong Date: Mon, 28 Nov 2022 16:42:37 +0100 Subject: mptcp: don't orphan ssk in mptcp_close() All of the subflows of a msk will be orphaned in mptcp_close(), which means the subflows are in DEAD state. After then, DATA_FIN will be sent, and the other side will response with a DATA_ACK for this DATA_FIN. However, if the other side still has pending data, the data that received on these subflows will not be passed to the msk, as they are DEAD and subflow_data_ready() will not be called in tcp_data_ready(). Therefore, these data can't be acked, and they will be retransmitted again and again, until timeout. Fix this by setting ssk->sk_socket and ssk->sk_wq to 'NULL', instead of orphaning the subflows in __mptcp_close(), as Paolo suggested. Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close") Reviewed-by: Biao Jiang Reviewed-by: Mengen Sun Signed-off-by: Menglong Dong Reviewed-by: Paolo Abeni Signed-off-by: Matthieu Baerts Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index b6dc6e260334..1dbc62537259 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2354,12 +2354,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, goto out; } - /* if we are invoked by the msk cleanup code, the subflow is - * already orphaned - */ - if (ssk->sk_socket) - sock_orphan(ssk); - + sock_orphan(ssk); subflow->disposable = 1; /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops @@ -2940,7 +2935,11 @@ cleanup: if (ssk == msk->first) subflow->fail_tout = 0; - sock_orphan(ssk); + /* detach from the parent socket, but allow data_ready to + * push incoming data into the mptcp stack, to properly ack it + */ + ssk->sk_socket = NULL; + ssk->sk_wq = NULL; unlock_sock_fast(ssk, slow); } sock_orphan(sk); -- cgit From b4f166651d03b5484fa179817ba8ad4899a5a6ac Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Mon, 28 Nov 2022 16:42:38 +0100 Subject: mptcp: fix sleep in atomic at close time Matt reported a splat at msk close time: BUG: sleeping function called from invalid context at net/mptcp/protocol.c:2877 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 155, name: packetdrill preempt_count: 201, expected: 0 RCU nest depth: 0, expected: 0 4 locks held by packetdrill/155: #0: ffff888001536990 (&sb->s_type->i_mutex_key#6){+.+.}-{3:3}, at: __sock_release (net/socket.c:650) #1: ffff88800b498130 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close (net/mptcp/protocol.c:2973) #2: ffff88800b49a130 (sk_lock-AF_INET/1){+.+.}-{0:0}, at: __mptcp_close_ssk (net/mptcp/protocol.c:2363) #3: ffff88800b49a0b0 (slock-AF_INET){+...}-{2:2}, at: __lock_sock_fast (include/net/sock.h:1820) Preemption disabled at: 0x0 CPU: 1 PID: 155 Comm: packetdrill Not tainted 6.1.0-rc5 #365 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) __might_resched.cold (kernel/sched/core.c:9891) __mptcp_destroy_sock (include/linux/kernel.h:110) __mptcp_close (net/mptcp/protocol.c:2959) mptcp_subflow_queue_clean (include/net/sock.h:1777) __mptcp_close_ssk (net/mptcp/protocol.c:2363) mptcp_destroy_common (net/mptcp/protocol.c:3170) mptcp_destroy (include/net/sock.h:1495) __mptcp_destroy_sock (net/mptcp/protocol.c:2886) __mptcp_close (net/mptcp/protocol.c:2959) mptcp_close (net/mptcp/protocol.c:2974) inet_release (net/ipv4/af_inet.c:432) __sock_release (net/socket.c:651) sock_close (net/socket.c:1367) __fput (fs/file_table.c:320) task_work_run (kernel/task_work.c:181 (discriminator 1)) exit_to_user_mode_prepare (include/linux/resume_user_mode.h:49) syscall_exit_to_user_mode (kernel/entry/common.c:130) do_syscall_64 (arch/x86/entry/common.c:87) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) We can't call mptcp_close under the 'fast' socket lock variant, replace it with a sock_lock_nested() as the relevant code is already under the listening msk socket lock protection. Reported-by: Matthieu Baerts Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/316 Fixes: 30e51b923e43 ("mptcp: fix unreleased socket in accept queue") Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts Signed-off-by: Matthieu Baerts Signed-off-by: Jakub Kicinski --- net/mptcp/subflow.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 02a54d59697b..2159b5f9988f 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1745,16 +1745,16 @@ void mptcp_subflow_queue_clean(struct sock *listener_ssk) for (msk = head; msk; msk = next) { struct sock *sk = (struct sock *)msk; - bool slow, do_cancel_work; + bool do_cancel_work; sock_hold(sk); - slow = lock_sock_fast_nested(sk); + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); next = msk->dl_next; msk->first = NULL; msk->dl_next = NULL; do_cancel_work = __mptcp_close(sk, 0); - unlock_sock_fast(sk, slow); + release_sock(sk); if (do_cancel_work) mptcp_cancel_work(sk); sock_put(sk); -- cgit