Commit f71dbf2f authored Jan 30, 2020 by David Howells

rxrpc: Fix insufficient receive notification generation



In rxrpc_input_data(), rxrpc_notify_socket() is called if the base sequence
number of the packet is immediately following the hard-ack point at the end
of the function.  However, this isn't sufficient, since the recvmsg side
may have been advancing the window and then overrun the position in which
we're adding - at which point rx_hard_ack >= seq0 and no notification is
generated.

Fix this by always generating a notification at the end of the input
function.

Without this, a long call may stall, possibly indefinitely.

Fixes: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>

parent fac20b9e

net/rxrpc/input.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -599,10 +599,8 @@ ack:
		false, true,
		rxrpc_propose_ack_input_data);

		if (seq0 == READ_ONCE(call->rx_hard_ack) + 1) {
		trace_rxrpc_notify_socket(call->debug_id, serial);
		rxrpc_notify_socket(call);
		}

		unlock:
		spin_unlock(&call->input_lock);

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