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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: 4faeee0cf8 ("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>
This commit is contained in:
Paolo Abeni 2023-10-11 09:20:55 +02:00 committed by Jakub Kicinski
parent 242e34500a
commit 419ce133ab
10 changed files with 80 additions and 45 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;
@ -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 @@ skip_copy:
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 +1596,12 @@ 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)) {
@ -1656,6 +1672,7 @@ 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 +1764,11 @@ 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 +1837,7 @@ 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 {
@ -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; \
})

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, 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, &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

@ -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;
}
@ -642,6 +640,7 @@ 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;
@ -696,6 +695,7 @@ 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 +704,11 @@ 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
@ -725,6 +730,7 @@ 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

@ -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;

16
net/ipv4/tcp.c
View File

@ -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);

4
net/ipv4/tcp_bpf.c
View File

@ -307,6 +307,8 @@ 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;
@ -351,6 +353,8 @@ msg_bytes_ready:
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;

7
net/mptcp/protocol.c
View File

@ -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).
@ -3173,7 +3167,6 @@ 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);

10
net/tls/tls_main.c
View File

@ -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;

19
net/tls/tls_sw.c
View File

@ -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);