From: David Howells dhowells@redhat.com
[ Upstream commit 4ba68c5192554876bd8c3afd904e3064d2915341 ]
If at the end of rxrpc sendmsg() or rxrpc_kernel_send_data() the call that was being given data was aborted remotely or otherwise failed, return an error rather than returning the amount of data buffered for transmission.
The call (presumably) did not complete, so there's not much point continuing with it. AF_RXRPC considers it "complete" and so will be unwilling to do anything else with it - and won't send a notification for it, deeming the return from sendmsg sufficient.
Not returning an error causes afs to incorrectly handle a StoreData operation that gets interrupted by a change of address due to NAT reconfiguration.
This doesn't normally affect most operations since their request parameters tend to fit into a single UDP packet and afs_make_call() returns before the server responds; StoreData is different as it involves transmission of a lot of data.
This can be triggered on a client by doing something like:
dd if=/dev/zero of=/afs/example.com/foo bs=1M count=512
at one prompt, and then changing the network address at another prompt, e.g.:
ifconfig enp6s0 inet 192.168.6.2 && route add 192.168.6.1 dev enp6s0
Tracing packets on an Auristor fileserver looks something like:
192.168.6.1 -> 192.168.6.3 RX 107 ACK Idle Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 192.168.6.3 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(64538) (64538) 192.168.6.3 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(64538) (64538) 192.168.6.1 -> 192.168.6.3 RX 107 ACK Idle Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 <ARP exchange for 192.168.6.2> 192.168.6.2 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(0) (0) 192.168.6.2 -> 192.168.6.1 AFS (RX) 1482 FS Request: Unknown(0) (0) 192.168.6.1 -> 192.168.6.2 RX 107 ACK Exceeds Window Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 192.168.6.1 -> 192.168.6.2 RX 74 ABORT Seq: 0 Call: 4 Source Port: 7000 Destination Port: 7001 192.168.6.1 -> 192.168.6.2 RX 74 ABORT Seq: 29321 Call: 4 Source Port: 7000 Destination Port: 7001
The Auristor fileserver logs code -453 (RXGEN_SS_UNMARSHAL), but the abort code received by kafs is -5 (RX_PROTOCOL_ERROR) as the rx layer sees the condition and generates an abort first and the unmarshal error is a consequence of that at the application layer.
Reported-by: Marc Dionne marc.dionne@auristor.com Signed-off-by: David Howells dhowells@redhat.com cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-December/004810.html # v1 Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/rxrpc/sendmsg.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index edd76c41765f..0220a2935002 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -440,6 +440,12 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
success: ret = copied; + if (READ_ONCE(call->state) == RXRPC_CALL_COMPLETE) { + read_lock_bh(&call->state_lock); + if (call->error < 0) + ret = call->error; + read_unlock_bh(&call->state_lock); + } out: call->tx_pending = skb; _leave(" = %d", ret);