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tcp: allow again tcp_disconnect() when threads are waiting 

JIRA: https://issues.redhat.com/browse/RHEL-12593
Tested: vs bz reproducer
Conflicts: the tls_sw chunk is mangling and applied in \
  tls_rx_reader_acquire(), as rhel lacks the upstream commit \
  f9ae3204fb45 ("net/tls: split  tls_rx_reader_lock"). \
  the wait_on_pending_writer() chunk did not contain the ONCE \
  annotation, as rhel lacks the upstream commit d0ac89f6f987 ("net: \
  deal with most data-races in sk_wait_event()"). The same for \
  sk_stream_wait_memory() chunk.

Upstream commit:
commit 419ce133ab928ab5efd7b50b2ef36ddfd4eadbd2
Author: Paolo Abeni <pabeni@redhat.com>
Date:   Wed Oct 11 09:20:55 2023 +0200

    tcp: allow again tcp_disconnect() when threads are waiting

    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 <tdeseyn@redhat.com>
    Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1886305
    Suggested-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>
    Reviewed-by: Eric Dumazet <edumazet@google.com>
    Link: https://lore.kernel.org/r/f3b95e47e3dbed840960548aebaa8d954372db41.1697008693.git.pabeni@redhat.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Paolo Abeni 2023-10-23 15:55:17 +02:00
parent 761fdf99de
commit 0240ed7c51
10 changed files with 79 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
View File

@ -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, &current_timeo, sk->sk_err ||
(sk->sk_shutdown & SEND_SHUTDOWN) ||
(csk_mem_free(cdev, sk) && !vm_wait), &wait);
ret = sk_wait_event(sk, &current_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;
@ -1438,6 +1441,7 @@ 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;
@ -1513,7 +1517,11 @@ 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) {
@ -1608,6 +1616,8 @@ skip_copy:
if (buffers_freed)
chtls_cleanup_rbuf(sk, copied);
unlock:
release_sock(sk);
return copied;
}
@ -1624,6 +1634,7 @@ 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, nonblock);
@ -1675,7 +1686,12 @@ 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) {
/* here 'copied' is 0 due to previous checks */
copied = ret;
break;
}
}
if (unlikely(peek_seq != tp->copied_seq)) {
@ -1746,6 +1762,7 @@ 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;
@ -1839,7 +1856,11 @@ 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:
@ -1908,6 +1929,7 @@ skip_copy:
if (buffers_freed)
chtls_cleanup_rbuf(sk, copied);
unlock:
release_sock(sk);
return copied;
}

10
include/net/sock.h
View File

@ -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 {
@ -1155,8 +1155,7 @@ 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) { \
@ -1166,8 +1165,7 @@ 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; \
})

12
net/core/stream.c
View File

@ -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, &current_timeo, sk->sk_err ||
(sk->sk_shutdown & SEND_SHUTDOWN) ||
(sk_stream_memory_free(sk) &&
!vm_wait), &wait);
ret = sk_wait_event(sk, &current_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;

10
net/ipv4/af_inet.c
View File

@ -593,7 +593,6 @@ 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_*.
@ -609,7 +608,6 @@ 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;
}
@ -638,6 +636,7 @@ int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
return -EINVAL;
if (uaddr->sa_family == AF_UNSPEC) {
sk->sk_disconnects++;
err = sk->sk_prot->disconnect(sk, flags);
sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
goto out;
@ -692,6 +691,7 @@ 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))
@ -700,6 +700,11 @@ 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
@ -721,6 +726,7 @@ out:
sock_error:
err = sock_error(sk) ? : -ECONNABORTED;
sock->state = SS_UNCONNECTED;
sk->sk_disconnects++;
if (sk->sk_prot->disconnect(sk, flags))
sock->state = SS_DISCONNECTING;
goto out;

1
net/ipv4/inet_connection_sock.c
View File

@ -963,7 +963,6 @@ 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;

16
net/ipv4/tcp.c
View File

@ -825,7 +825,9 @@ 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;
@ -2553,7 +2555,11 @@ static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
release_sock(sk);
lock_sock(sk);
} else {
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) &&
@ -3078,12 +3084,6 @@ 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);

4
net/ipv4/tcp_bpf.c
View File

@ -229,6 +229,8 @@ msg_bytes_ready:
}
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;
@ -268,6 +270,8 @@ msg_bytes_ready:
timeo = sock_rcvtimeo(sk, nonblock);
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;

7
net/mptcp/protocol.c
View File

@ -3092,12 +3092,6 @@ 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).
@ -3163,7 +3157,6 @@ struct sock *mptcp_sk_clone(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);

9
net/tls/tls_main.c
View File

@ -96,8 +96,8 @@ 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) {
@ -111,8 +111,13 @@ int wait_on_pending_writer(struct sock *sk, long *timeo)
break;
}
if (sk_wait_event(sk, timeo, !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;

18
net/tls/tls_sw.c
View File

@ -1296,6 +1296,7 @@ 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);
@ -1307,6 +1308,9 @@ 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))
@ -1325,10 +1329,10 @@ 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);
@ -1869,8 +1873,8 @@ static int tls_rx_reader_lock(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);
err = sk_wait_event(sk, &timeo,
!READ_ONCE(ctx->reader_present), &wait);
remove_wait_queue(&ctx->wq, &wait);
if (timeo <= 0) {
@ -1881,6 +1885,8 @@ static int tls_rx_reader_lock(struct sock *sk, struct tls_sw_context_rx *ctx,
err = sock_intr_errno(timeo);
goto err_unlock;
}
if (err < 0)
goto err_unlock;
}
WRITE_ONCE(ctx->reader_present, 1);