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Merge branch 'net-avoid-KCSAN-splats'

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Eric Dumazet says:

====================
net: avoid KCSAN splats

Often times we use skb_queue_empty() without holding a lock,
meaning that other cpus (or interrupt) can change the queue
under us. This is fine, but we need to properly annotate
the lockless intent to make sure the compiler wont over
optimize things.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2019-10-28 13:33:41 -07:00
commit 2024305863
18 changed files with 56 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/crypto/chelsio/chtls/chtls_io.c
View File

@ -1702,7 +1702,7 @@ int chtls_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
return peekmsg(sk, msg, len, nonblock, flags);
if (sk_can_busy_loop(sk) &&
skb_queue_empty(&sk->sk_receive_queue) &&
skb_queue_empty_lockless(&sk->sk_receive_queue) &&
sk->sk_state == TCP_ESTABLISHED)
sk_busy_loop(sk, nonblock);

2
drivers/isdn/capi/capi.c
View File

@ -744,7 +744,7 @@ capi_poll(struct file *file, poll_table *wait)
poll_wait(file, &(cdev->recvwait), wait);
mask = EPOLLOUT | EPOLLWRNORM;
if (!skb_queue_empty(&cdev->recvqueue))
if (!skb_queue_empty_lockless(&cdev->recvqueue))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}

2
drivers/nvme/host/tcp.c
View File

@ -2219,7 +2219,7 @@ static int nvme_tcp_poll(struct blk_mq_hw_ctx *hctx)
struct nvme_tcp_queue *queue = hctx->driver_data;
struct sock *sk = queue->sock->sk;
if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue))
if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue))
sk_busy_loop(sk, true);
nvme_tcp_try_recv(queue);
return queue->nr_cqe;

33
include/linux/skbuff.h
View File

@ -1495,6 +1495,19 @@ static inline int skb_queue_empty(const struct sk_buff_head *list)
return list->next == (const struct sk_buff *) list;
}
/**
* skb_queue_empty_lockless - check if a queue is empty
* @list: queue head
*
* Returns true if the queue is empty, false otherwise.
* This variant can be used in lockless contexts.
*/
static inline bool skb_queue_empty_lockless(const struct sk_buff_head *list)
{
return READ_ONCE(list->next) == (const struct sk_buff *) list;
}
/**
* skb_queue_is_last - check if skb is the last entry in the queue
* @list: queue head
@ -1848,9 +1861,11 @@ static inline void __skb_insert(struct sk_buff *newsk,
struct sk_buff *prev, struct sk_buff *next,
struct sk_buff_head *list)
{
newsk->next = next;
newsk->prev = prev;
next->prev = prev->next = newsk;
/* see skb_queue_empty_lockless() for the opposite READ_ONCE() */
WRITE_ONCE(newsk->next, next);
WRITE_ONCE(newsk->prev, prev);
WRITE_ONCE(next->prev, newsk);
WRITE_ONCE(prev->next, newsk);
list->qlen++;
}
@ -1861,11 +1876,11 @@ static inline void __skb_queue_splice(const struct sk_buff_head *list,
struct sk_buff *first = list->next;
struct sk_buff *last = list->prev;
first->prev = prev;
prev->next = first;
WRITE_ONCE(first->prev, prev);
WRITE_ONCE(prev->next, first);
last->next = next;
next->prev = last;
WRITE_ONCE(last->next, next);
WRITE_ONCE(next->prev, last);
}
/**
@ -2006,8 +2021,8 @@ static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
next = skb->next;
prev = skb->prev;
skb->next = skb->prev = NULL;
next->prev = prev;
prev->next = next;
WRITE_ONCE(next->prev, prev);
WRITE_ONCE(prev->next, next);
}
/**

2
net/atm/common.c
View File

@ -668,7 +668,7 @@ __poll_t vcc_poll(struct file *file, struct socket *sock, poll_table *wait)
mask |= EPOLLHUP;
/* readable? */
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* writable? */

4
net/bluetooth/af_bluetooth.c
View File

@ -460,7 +460,7 @@ __poll_t bt_sock_poll(struct file *file, struct socket *sock,
if (sk->sk_state == BT_LISTEN)
return bt_accept_poll(sk);
if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
mask |= EPOLLERR |
(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
@ -470,7 +470,7 @@ __poll_t bt_sock_poll(struct file *file, struct socket *sock,
if (sk->sk_shutdown == SHUTDOWN_MASK)
mask |= EPOLLHUP;
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
if (sk->sk_state == BT_CLOSED)

2
net/caif/caif_socket.c
View File

@ -953,7 +953,7 @@ static __poll_t caif_poll(struct file *file,
mask |= EPOLLRDHUP;
/* readable? */
if (!skb_queue_empty(&sk->sk_receive_queue) ||
if (!skb_queue_empty_lockless(&sk->sk_receive_queue) ||
(sk->sk_shutdown & RCV_SHUTDOWN))
mask |= EPOLLIN | EPOLLRDNORM;

8
net/core/datagram.c
View File

@ -97,7 +97,7 @@ int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
if (error)
goto out_err;
if (sk->sk_receive_queue.prev != skb)
if (READ_ONCE(sk->sk_receive_queue.prev) != skb)
goto out;
/* Socket shut down? */
@ -278,7 +278,7 @@ struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned int flags,
break;
sk_busy_loop(sk, flags & MSG_DONTWAIT);
} while (sk->sk_receive_queue.prev != *last);
} while (READ_ONCE(sk->sk_receive_queue.prev) != *last);
error = -EAGAIN;
@ -767,7 +767,7 @@ __poll_t datagram_poll(struct file *file, struct socket *sock,
mask = 0;
/* exceptional events? */
if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
mask |= EPOLLERR |
(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
@ -777,7 +777,7 @@ __poll_t datagram_poll(struct file *file, struct socket *sock,
mask |= EPOLLHUP;
/* readable? */
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* Connection-based need to check for termination and startup */

2
net/core/sock.c
View File

@ -3600,7 +3600,7 @@ bool sk_busy_loop_end(void *p, unsigned long start_time)
{
struct sock *sk = p;
return !skb_queue_empty(&sk->sk_receive_queue) ||
return !skb_queue_empty_lockless(&sk->sk_receive_queue) ||
sk_busy_loop_timeout(sk, start_time);
}
EXPORT_SYMBOL(sk_busy_loop_end);

2
net/decnet/af_decnet.c
View File

@ -1205,7 +1205,7 @@ static __poll_t dn_poll(struct file *file, struct socket *sock, poll_table *wai
struct dn_scp *scp = DN_SK(sk);
__poll_t mask = datagram_poll(file, sock, wait);
if (!skb_queue_empty(&scp->other_receive_queue))
if (!skb_queue_empty_lockless(&scp->other_receive_queue))
mask |= EPOLLRDBAND;
return mask;

4
net/ipv4/tcp.c
View File

@ -584,7 +584,7 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
}
/* This barrier is coupled with smp_wmb() in tcp_reset() */
smp_rmb();
if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
mask |= EPOLLERR;
return mask;
@ -1964,7 +1964,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
if (unlikely(flags & MSG_ERRQUEUE))
return inet_recv_error(sk, msg, len, addr_len);
if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue) &&
(sk->sk_state == TCP_ESTABLISHED))
sk_busy_loop(sk, nonblock);

8
net/ipv4/udp.c
View File

@ -1577,7 +1577,7 @@ static int first_packet_length(struct sock *sk)
spin_lock_bh(&rcvq->lock);
skb = __first_packet_length(sk, rcvq, &total);
if (!skb && !skb_queue_empty(sk_queue)) {
if (!skb && !skb_queue_empty_lockless(sk_queue)) {
spin_lock(&sk_queue->lock);
skb_queue_splice_tail_init(sk_queue, rcvq);
spin_unlock(&sk_queue->lock);
@ -1650,7 +1650,7 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
return skb;
}
if (skb_queue_empty(sk_queue)) {
if (skb_queue_empty_lockless(sk_queue)) {
spin_unlock_bh(&queue->lock);
goto busy_check;
}
@ -1676,7 +1676,7 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
break;
sk_busy_loop(sk, flags & MSG_DONTWAIT);
} while (!skb_queue_empty(sk_queue));
} while (!skb_queue_empty_lockless(sk_queue));
/* sk_queue is empty, reader_queue may contain peeked packets */
} while (timeo &&
@ -2712,7 +2712,7 @@ __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait)
__poll_t mask = datagram_poll(file, sock, wait);
struct sock *sk = sock->sk;
if (!skb_queue_empty(&udp_sk(sk)->reader_queue))
if (!skb_queue_empty_lockless(&udp_sk(sk)->reader_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* Check for false positives due to checksum errors */

4
net/nfc/llcp_sock.c
View File

@ -554,11 +554,11 @@ static __poll_t llcp_sock_poll(struct file *file, struct socket *sock,
if (sk->sk_state == LLCP_LISTEN)
return llcp_accept_poll(sk);
if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
mask |= EPOLLERR |
(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
if (sk->sk_state == LLCP_CLOSED)

4
net/phonet/socket.c
View File

@ -338,9 +338,9 @@ static __poll_t pn_socket_poll(struct file *file, struct socket *sock,
if (sk->sk_state == TCP_CLOSE)
return EPOLLERR;
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
if (!skb_queue_empty(&pn->ctrlreq_queue))
if (!skb_queue_empty_lockless(&pn->ctrlreq_queue))
mask |= EPOLLPRI;
if (!mask && sk->sk_state == TCP_CLOSE_WAIT)
return EPOLLHUP;

6
net/sctp/socket.c
View File

@ -8476,7 +8476,7 @@ __poll_t sctp_poll(struct file *file, struct socket *sock, poll_table *wait)
mask = 0;
/* Is there any exceptional events? */
if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
mask |= EPOLLERR |
(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
if (sk->sk_shutdown & RCV_SHUTDOWN)
@ -8485,7 +8485,7 @@ __poll_t sctp_poll(struct file *file, struct socket *sock, poll_table *wait)
mask |= EPOLLHUP;
/* Is it readable? Reconsider this code with TCP-style support. */
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* The association is either gone or not ready. */
@ -8871,7 +8871,7 @@ struct sk_buff *sctp_skb_recv_datagram(struct sock *sk, int flags,
if (sk_can_busy_loop(sk)) {
sk_busy_loop(sk, noblock);
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
continue;
}

4
net/tipc/socket.c
View File

@ -740,7 +740,7 @@ static __poll_t tipc_poll(struct file *file, struct socket *sock,
/* fall through */
case TIPC_LISTEN:
case TIPC_CONNECTING:
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
revents |= EPOLLIN | EPOLLRDNORM;
break;
case TIPC_OPEN:
@ -748,7 +748,7 @@ static __poll_t tipc_poll(struct file *file, struct socket *sock,
revents |= EPOLLOUT;
if (!tipc_sk_type_connectionless(sk))
break;
if (skb_queue_empty(&sk->sk_receive_queue))
if (skb_queue_empty_lockless(&sk->sk_receive_queue))
break;
revents |= EPOLLIN | EPOLLRDNORM;
break;

6
net/unix/af_unix.c
View File

@ -2599,7 +2599,7 @@ static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wa
mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
/* readable? */
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* Connection-based need to check for termination and startup */
@ -2628,7 +2628,7 @@ static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
mask = 0;
/* exceptional events? */
if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
mask |= EPOLLERR |
(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
@ -2638,7 +2638,7 @@ static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
mask |= EPOLLHUP;
/* readable? */
if (!skb_queue_empty(&sk->sk_receive_queue))
if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* Connection-based need to check for termination and startup */

2
net/vmw_vsock/af_vsock.c
View File

@ -870,7 +870,7 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
* the queue and write as long as the socket isn't shutdown for
* sending.
*/
if (!skb_queue_empty(&sk->sk_receive_queue) ||
if (!skb_queue_empty_lockless(&sk->sk_receive_queue) ||
(sk->sk_shutdown & RCV_SHUTDOWN)) {
mask |= EPOLLIN | EPOLLRDNORM;
}