From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 406702746B; Tue, 10 Oct 2023 15:50:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ju3cyw0m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A319C433C7; Tue, 10 Oct 2023 15:50:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696953001; bh=BKoKejiorqNl3nfK3YQCqz/J0MspBYeqcP2yz3i0mqU=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=ju3cyw0mIeQ/RlkjV7kykjMV+Rbv1iB7BsPKmtYUXrc3KujJmQ7j2zYOnuHIRMUGc z2A37l6fvxG9v6K+BXh9vutqbkD6cAn0AUWEYhR5JrIBMqN0Wy9kNkdKpjewlc7SAH tvdqkRDEdXLVuuvc6SVBQlfPi9W2EINOX1BtEJ0n5DtTJ0mF1Yw+9ShrSuHPTGF/V7 fHNwNR/PS2V0GJILX6Ni2sQA9qncHZUBAmBABRK/GyIuyATkSqExTYYrM05uzF/4TK znc3v3Iryr9H4xdP/bYM4bkTq99gqtZEBQ8EhCxqGXMiPXAPHHVXRZvjzk+e91Q690 2gzQlVv5JDqcg== Date: Tue, 10 Oct 2023 08:50:00 -0700 (PDT) From: Mat Martineau To: Paolo Abeni cc: netdev@vger.kernel.org, Ayush Sawal , "David S. Miller" , Eric Dumazet , Jakub Kicinski , David Ahern , mptcp@lists.linux.dev, Boris Pismenny , Tom Deseyn Subject: Re: [PATCH net] tcp: allow again tcp_disconnect() when threads are waiting In-Reply-To: <1d0e4528ab057a246fd8c60b91cffd34f277b957.1696848602.git.pabeni@redhat.com> Message-ID: References: <1d0e4528ab057a246fd8c60b91cffd34f277b957.1696848602.git.pabeni@redhat.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset=US-ASCII On Mon, 9 Oct 2023, Paolo Abeni wrote: > As reported by Tom, .NET and applications build on top of it rely > on connect(AF_UNSPEC) to async cancel pending I/O operations on TCP > socket. > > The blamed commit below caused a regression, as such cancellation > can now fail. > > As suggested by Eric, this change addresses the problem explicitly > causing blocking I/O operation to terminate immediately (with an error) > when a concurrent disconnect() is executed. > > Instead of tracking the number of threads blocked on a given socket, > track the number of disconnect() issued on such socket. If such counter > changes after a blocking operation releasing and re-acquiring the socket > lock, error out the current operation. > > Fixes: 4faeee0cf8a5 ("tcp: deny tcp_disconnect() when threads are waiting") > Reported-by: Tom Deseyn > Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1886305 > Suggested-by: Eric Dumazet > Signed-off-by: Paolo Abeni For MPTCP changes: Acked-by: Mat Martineau > --- > .../chelsio/inline_crypto/chtls/chtls_io.c | 35 +++++++++++++++---- > include/net/sock.h | 10 +++--- > net/core/stream.c | 12 ++++--- > net/ipv4/af_inet.c | 8 +++-- > net/ipv4/inet_connection_sock.c | 1 - > net/ipv4/tcp.c | 17 ++++----- > net/ipv4/tcp_bpf.c | 4 +++ > net/mptcp/protocol.c | 8 +---- > net/tls/tls_main.c | 10 ++++-- > net/tls/tls_sw.c | 19 ++++++---- > 10 files changed, 79 insertions(+), 45 deletions(-) > > diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c > index 5fc64e47568a..caa1eaed190d 100644 > --- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c > +++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c > @@ -911,7 +911,7 @@ static int csk_wait_memory(struct chtls_dev *cdev, > struct sock *sk, long *timeo_p) > { > DEFINE_WAIT_FUNC(wait, woken_wake_function); > - int err = 0; > + int ret, err = 0; > long current_timeo; > long vm_wait = 0; > bool noblock; > @@ -942,10 +942,13 @@ static int csk_wait_memory(struct chtls_dev *cdev, > > set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); > sk->sk_write_pending++; > - sk_wait_event(sk, ¤t_timeo, sk->sk_err || > - (sk->sk_shutdown & SEND_SHUTDOWN) || > - (csk_mem_free(cdev, sk) && !vm_wait), &wait); > + ret = sk_wait_event(sk, ¤t_timeo, sk->sk_err || > + (sk->sk_shutdown & SEND_SHUTDOWN) || > + (csk_mem_free(cdev, sk) && !vm_wait), > + &wait); > sk->sk_write_pending--; > + if (ret < 0) > + goto do_error; > > if (vm_wait) { > vm_wait -= current_timeo; > @@ -1348,6 +1351,7 @@ static int chtls_pt_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > int copied = 0; > int target; > long timeo; > + int ret; > > buffers_freed = 0; > > @@ -1423,7 +1427,11 @@ static int chtls_pt_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > if (copied >= target) > break; > chtls_cleanup_rbuf(sk, copied); > - sk_wait_data(sk, &timeo, NULL); > + ret = sk_wait_data(sk, &timeo, NULL); > + if (ret < 0) { > + copied = copied ? : ret; > + goto unlock; > + } > continue; > found_ok_skb: > if (!skb->len) { > @@ -1518,6 +1526,8 @@ static int chtls_pt_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > if (buffers_freed) > chtls_cleanup_rbuf(sk, copied); > + > +unlock: > release_sock(sk); > return copied; > } > @@ -1534,6 +1544,7 @@ static int peekmsg(struct sock *sk, struct msghdr *msg, > int copied = 0; > size_t avail; /* amount of available data in current skb */ > long timeo; > + int ret; > > lock_sock(sk); > timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); > @@ -1585,7 +1596,11 @@ static int peekmsg(struct sock *sk, struct msghdr *msg, > release_sock(sk); > lock_sock(sk); > } else { > - sk_wait_data(sk, &timeo, NULL); > + ret = sk_wait_data(sk, &timeo, NULL); > + if (ret < 0) { > + copied = ret; > + break; > + } > } > > if (unlikely(peek_seq != tp->copied_seq)) { > @@ -1656,6 +1671,7 @@ int chtls_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > int copied = 0; > long timeo; > int target; /* Read at least this many bytes */ > + int ret; > > buffers_freed = 0; > > @@ -1747,7 +1763,11 @@ int chtls_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > if (copied >= target) > break; > chtls_cleanup_rbuf(sk, copied); > - sk_wait_data(sk, &timeo, NULL); > + ret = sk_wait_data(sk, &timeo, NULL); > + if (ret < 0) { > + copied = copied ? : ret; > + goto unlock; > + } > continue; > > found_ok_skb: > @@ -1816,6 +1836,7 @@ int chtls_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > if (buffers_freed) > chtls_cleanup_rbuf(sk, copied); > > +unlock: > release_sock(sk); > return copied; > } > diff --git a/include/net/sock.h b/include/net/sock.h > index b770261fbdaf..92f7ea62a915 100644 > --- a/include/net/sock.h > +++ b/include/net/sock.h > @@ -336,7 +336,7 @@ struct sk_filter; > * @sk_cgrp_data: cgroup data for this cgroup > * @sk_memcg: this socket's memory cgroup association > * @sk_write_pending: a write to stream socket waits to start > - * @sk_wait_pending: number of threads blocked on this socket > + * @sk_disconnects: number of disconnect operations performed on this sock > * @sk_state_change: callback to indicate change in the state of the sock > * @sk_data_ready: callback to indicate there is data to be processed > * @sk_write_space: callback to indicate there is bf sending space available > @@ -429,7 +429,7 @@ struct sock { > unsigned int sk_napi_id; > #endif > int sk_rcvbuf; > - int sk_wait_pending; > + int sk_disconnects; > > struct sk_filter __rcu *sk_filter; > union { > @@ -1189,8 +1189,7 @@ static inline void sock_rps_reset_rxhash(struct sock *sk) > } > > #define sk_wait_event(__sk, __timeo, __condition, __wait) \ > - ({ int __rc; \ > - __sk->sk_wait_pending++; \ > + ({ int __rc, __dis = __sk->sk_disconnects; \ > release_sock(__sk); \ > __rc = __condition; \ > if (!__rc) { \ > @@ -1200,8 +1199,7 @@ static inline void sock_rps_reset_rxhash(struct sock *sk) > } \ > sched_annotate_sleep(); \ > lock_sock(__sk); \ > - __sk->sk_wait_pending--; \ > - __rc = __condition; \ > + __rc = __dis == __sk->sk_disconnects ? __condition : -EPIPE; \ > __rc; \ > }) > > diff --git a/net/core/stream.c b/net/core/stream.c > index f5c4e47df165..96fbcb9bbb30 100644 > --- a/net/core/stream.c > +++ b/net/core/stream.c > @@ -117,7 +117,7 @@ EXPORT_SYMBOL(sk_stream_wait_close); > */ > int sk_stream_wait_memory(struct sock *sk, long *timeo_p) > { > - int err = 0; > + int ret, err = 0; > long vm_wait = 0; > long current_timeo = *timeo_p; > DEFINE_WAIT_FUNC(wait, woken_wake_function); > @@ -142,11 +142,13 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p) > > set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); > sk->sk_write_pending++; > - sk_wait_event(sk, ¤t_timeo, READ_ONCE(sk->sk_err) || > - (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) || > - (sk_stream_memory_free(sk) && > - !vm_wait), &wait); > + ret = sk_wait_event(sk, ¤t_timeo, READ_ONCE(sk->sk_err) || > + (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) || > + (sk_stream_memory_free(sk) && !vm_wait), > + &wait); > sk->sk_write_pending--; > + if (ret < 0) > + goto do_error; > > if (vm_wait) { > vm_wait -= current_timeo; > diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c > index 3d2e30e20473..a7aa082f9a4c 100644 > --- a/net/ipv4/af_inet.c > +++ b/net/ipv4/af_inet.c > @@ -597,7 +597,6 @@ static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias) > > add_wait_queue(sk_sleep(sk), &wait); > sk->sk_write_pending += writebias; > - sk->sk_wait_pending++; > > /* Basic assumption: if someone sets sk->sk_err, he _must_ > * change state of the socket from TCP_SYN_*. > @@ -613,7 +612,6 @@ static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias) > } > remove_wait_queue(sk_sleep(sk), &wait); > sk->sk_write_pending -= writebias; > - sk->sk_wait_pending--; > return timeo; > } > > @@ -696,6 +694,7 @@ int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr, > int writebias = (sk->sk_protocol == IPPROTO_TCP) && > tcp_sk(sk)->fastopen_req && > tcp_sk(sk)->fastopen_req->data ? 1 : 0; > + int dis = sk->sk_disconnects; > > /* Error code is set above */ > if (!timeo || !inet_wait_for_connect(sk, timeo, writebias)) > @@ -704,6 +703,11 @@ int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr, > err = sock_intr_errno(timeo); > if (signal_pending(current)) > goto out; > + > + if (dis != sk->sk_disconnects) { > + err = -EPIPE; > + goto out; > + } > } > > /* Connection was closed by RST, timeout, ICMP error > diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c > index aeebe8816689..394a498c2823 100644 > --- a/net/ipv4/inet_connection_sock.c > +++ b/net/ipv4/inet_connection_sock.c > @@ -1145,7 +1145,6 @@ struct sock *inet_csk_clone_lock(const struct sock *sk, > if (newsk) { > struct inet_connection_sock *newicsk = inet_csk(newsk); > > - newsk->sk_wait_pending = 0; > inet_sk_set_state(newsk, TCP_SYN_RECV); > newicsk->icsk_bind_hash = NULL; > newicsk->icsk_bind2_hash = NULL; > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 3f66cdeef7de..368f0d16c817 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -831,7 +831,9 @@ ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, > */ > if (!skb_queue_empty(&sk->sk_receive_queue)) > break; > - sk_wait_data(sk, &timeo, NULL); > + ret = sk_wait_data(sk, &timeo, NULL); > + if (ret < 0) > + break; > if (signal_pending(current)) { > ret = sock_intr_errno(timeo); > break; > @@ -2442,7 +2444,11 @@ static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len, > __sk_flush_backlog(sk); > } else { > tcp_cleanup_rbuf(sk, copied); > - sk_wait_data(sk, &timeo, last); > + err = sk_wait_data(sk, &timeo, last); > + if (err < 0) { > + err = copied ? : err; > + goto out; > + } > } > > if ((flags & MSG_PEEK) && > @@ -2966,12 +2972,6 @@ int tcp_disconnect(struct sock *sk, int flags) > int old_state = sk->sk_state; > u32 seq; > > - /* Deny disconnect if other threads are blocked in sk_wait_event() > - * or inet_wait_for_connect(). > - */ > - if (sk->sk_wait_pending) > - return -EBUSY; > - > if (old_state != TCP_CLOSE) > tcp_set_state(sk, TCP_CLOSE); > > @@ -3092,6 +3092,7 @@ int tcp_disconnect(struct sock *sk, int flags) > sk->sk_frag.offset = 0; > } > sk_error_report(sk); > + sk->sk_disconnects++; > return 0; > } > EXPORT_SYMBOL(tcp_disconnect); > diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c > index 327268203001..ba2e92188124 100644 > --- a/net/ipv4/tcp_bpf.c > +++ b/net/ipv4/tcp_bpf.c > @@ -307,6 +307,8 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk, > } > > data = tcp_msg_wait_data(sk, psock, timeo); > + if (data < 0) > + return data; > if (data && !sk_psock_queue_empty(psock)) > goto msg_bytes_ready; > copied = -EAGAIN; > @@ -351,6 +353,8 @@ static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); > data = tcp_msg_wait_data(sk, psock, timeo); > + if (data < 0) > + return data; > if (data) { > if (!sk_psock_queue_empty(psock)) > goto msg_bytes_ready; > diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c > index e252539b1e19..22dd27cce4e6 100644 > --- a/net/mptcp/protocol.c > +++ b/net/mptcp/protocol.c > @@ -3098,12 +3098,6 @@ static int mptcp_disconnect(struct sock *sk, int flags) > { > struct mptcp_sock *msk = mptcp_sk(sk); > > - /* Deny disconnect if other threads are blocked in sk_wait_event() > - * or inet_wait_for_connect(). > - */ > - if (sk->sk_wait_pending) > - return -EBUSY; > - > /* We are on the fastopen error path. We can't call straight into the > * subflows cleanup code due to lock nesting (we are already under > * msk->firstsocket lock). > @@ -3144,6 +3138,7 @@ static int mptcp_disconnect(struct sock *sk, int flags) > > WRITE_ONCE(sk->sk_shutdown, 0); > sk_error_report(sk); > + sk->sk_disconnects++; > return 0; > } > > @@ -3173,7 +3168,6 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk, > inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); > #endif > > - nsk->sk_wait_pending = 0; > __mptcp_init_sock(nsk); > > msk = mptcp_sk(nsk); > diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c > index 02f583ff9239..002483e60c19 100644 > --- a/net/tls/tls_main.c > +++ b/net/tls/tls_main.c > @@ -139,8 +139,8 @@ void update_sk_prot(struct sock *sk, struct tls_context *ctx) > > int wait_on_pending_writer(struct sock *sk, long *timeo) > { > - int rc = 0; > DEFINE_WAIT_FUNC(wait, woken_wake_function); > + int ret, rc = 0; > > add_wait_queue(sk_sleep(sk), &wait); > while (1) { > @@ -154,9 +154,13 @@ int wait_on_pending_writer(struct sock *sk, long *timeo) > break; > } > > - if (sk_wait_event(sk, timeo, > - !READ_ONCE(sk->sk_write_pending), &wait)) > + ret = sk_wait_event(sk, timeo, > + !READ_ONCE(sk->sk_write_pending), &wait); > + if (ret) { > + if (ret < 0) > + rc = ret; > break; > + } > } > remove_wait_queue(sk_sleep(sk), &wait); > return rc; > diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c > index d1fc295b83b5..e9d1e83a859d 100644 > --- a/net/tls/tls_sw.c > +++ b/net/tls/tls_sw.c > @@ -1291,6 +1291,7 @@ tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock, > struct tls_context *tls_ctx = tls_get_ctx(sk); > struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx); > DEFINE_WAIT_FUNC(wait, woken_wake_function); > + int ret = 0; > long timeo; > > timeo = sock_rcvtimeo(sk, nonblock); > @@ -1302,6 +1303,9 @@ tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock, > if (sk->sk_err) > return sock_error(sk); > > + if (ret < 0) > + return ret; > + > if (!skb_queue_empty(&sk->sk_receive_queue)) { > tls_strp_check_rcv(&ctx->strp); > if (tls_strp_msg_ready(ctx)) > @@ -1320,10 +1324,10 @@ tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock, > released = true; > add_wait_queue(sk_sleep(sk), &wait); > sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); > - sk_wait_event(sk, &timeo, > - tls_strp_msg_ready(ctx) || > - !sk_psock_queue_empty(psock), > - &wait); > + ret = sk_wait_event(sk, &timeo, > + tls_strp_msg_ready(ctx) || > + !sk_psock_queue_empty(psock), > + &wait); > sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); > remove_wait_queue(sk_sleep(sk), &wait); > > @@ -1852,6 +1856,7 @@ static int tls_rx_reader_acquire(struct sock *sk, struct tls_sw_context_rx *ctx, > bool nonblock) > { > long timeo; > + int ret; > > timeo = sock_rcvtimeo(sk, nonblock); > > @@ -1861,14 +1866,16 @@ static int tls_rx_reader_acquire(struct sock *sk, struct tls_sw_context_rx *ctx, > ctx->reader_contended = 1; > > add_wait_queue(&ctx->wq, &wait); > - sk_wait_event(sk, &timeo, > - !READ_ONCE(ctx->reader_present), &wait); > + ret = sk_wait_event(sk, &timeo, > + !READ_ONCE(ctx->reader_present), &wait); > remove_wait_queue(&ctx->wq, &wait); > > if (timeo <= 0) > return -EAGAIN; > if (signal_pending(current)) > return sock_intr_errno(timeo); > + if (ret < 0) > + return ret; > } > > WRITE_ONCE(ctx->reader_present, 1); > -- > 2.41.0 > > >