Commit 45e77d31 authored Jul 19, 2010 by Ilpo Järvinen Committed by David S. Miller Jul 19, 2010

tcp: fix crash in tcp_xmit_retransmit_queue



It can happen that there are no packets in queue while calling
tcp_xmit_retransmit_queue(). tcp_write_queue_head() then returns
NULL and that gets deref'ed to get sacked into a local var.

There is no work to do if no packets are outstanding so we just
exit early.

This oops was introduced by 08ebd172 (tcp: remove tp->lost_out
guard to make joining diff nicer).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Reported-by: Lennart Schulte <lennart.schulte@nets.rwth-aachen.de>
Tested-by: Lennart Schulte <lennart.schulte@nets.rwth-aachen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b508998f

net/ipv4/tcp_output.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -2208,6 +2208,9 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
		int mib_idx;
		int fwd_rexmitting = 0;

		if (!tp->packets_out)
		return;

		if (!tp->lost_out)
		tp->retransmit_high = tp->snd_una;

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