Messages in this thread | | | Subject | Re: [PATCHv2] tcp: fix crash in tcp_xmit_retransmit_queue | From | Eric Dumazet <> | Date | Mon, 19 Jul 2010 16:09:15 +0200 |
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Le lundi 19 juillet 2010 à 14:16 +0300, Ilpo Järvinen a écrit :
> Thanks for testing. > > DaveM, I think this oops was introduced for 2.6.28 (in > 08ebd1721ab8fd362e90ae17b461c07b23fa2824 it seems, to be exact) so to > stables it should go too please. I've only tweaked the message (so no need > for Lennart to retest v2 :-)). > > -- > [PATCHv2] 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 08ebd1721ab8fd (tcp: remove tp->lost_out > guard to make joining diff nicer). >
But prior to commit 08ebd1721ab8fd3, we were not testing tp->packets_out, but tp->lost_out
if it was 0, we were not doing the tcp_for_write_queue_from() loop.
Not sure it makes a difference ?
> 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> > --- > net/ipv4/tcp_output.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c > index b4ed957..7ed9dc1 100644 > --- a/net/ipv4/tcp_output.c > +++ b/net/ipv4/tcp_output.c > @@ -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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