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| author | David Howells <dhowells@redhat.com> | 2016-03-04 15:58:06 +0000 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2016-03-04 15:58:06 +0000 |
| commit | ee72b9fddb41a2087b4a7aa74791ef1700f3f6cc (patch) | |
| tree | 36725c70bc83ff45d66bdb4f7b3377d09722e4e7 /net/rxrpc | |
| parent | b4f1342f915201ee15ef6890857b5469879ee402 (diff) | |
| download | lwn-ee72b9fddb41a2087b4a7aa74791ef1700f3f6cc.tar.gz lwn-ee72b9fddb41a2087b4a7aa74791ef1700f3f6cc.zip | |
rxrpc: Use ACCESS_ONCE() when accessing circular buffer pointers
Use ACCESS_ONCE() when accessing the other-end pointer into a circular
buffer as it's possible the other-end pointer might change whilst we're
doing this, and if we access it twice, we might get some weird things
happening.
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'net/rxrpc')
| -rw-r--r-- | net/rxrpc/ar-output.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c index 353f5c9141ea..14c8df6b7f41 100644 --- a/net/rxrpc/ar-output.c +++ b/net/rxrpc/ar-output.c @@ -401,7 +401,8 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx, int ret; _enter(",{%d},%ld", - CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz), + CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail), + call->acks_winsz), *timeo); add_wait_queue(&call->tx_waitq, &myself); @@ -409,7 +410,7 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx, for (;;) { set_current_state(TASK_INTERRUPTIBLE); ret = 0; - if (CIRC_SPACE(call->acks_head, call->acks_tail, + if (CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail), call->acks_winsz) > 0) break; if (signal_pending(current)) { @@ -570,7 +571,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx, _debug("alloc"); - if (CIRC_SPACE(call->acks_head, call->acks_tail, + if (CIRC_SPACE(call->acks_head, + ACCESS_ONCE(call->acks_tail), call->acks_winsz) <= 0) { ret = -EAGAIN; if (msg->msg_flags & MSG_DONTWAIT) @@ -686,7 +688,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx, sp->hdr.flags = conn->out_clientflag; if (msg_data_left(msg) == 0 && !more) sp->hdr.flags |= RXRPC_LAST_PACKET; - else if (CIRC_SPACE(call->acks_head, call->acks_tail, + else if (CIRC_SPACE(call->acks_head, + ACCESS_ONCE(call->acks_tail), call->acks_winsz) > 1) sp->hdr.flags |= RXRPC_MORE_PACKETS; if (more && seq & 1) |