From: Yuchung Cheng <ych...@google.com> Date: Wed, 31 May 2017 11:21:27 -0700
> When the sender switches its congestion control during loss > recovery, if the recovery is spurious then it may incorrectly > revert cwnd and ssthresh to the older values set by a previous > congestion control. Consider a congestion control (like BBR) > that does not use ssthresh and keeps it infinite: the connection > may incorrectly revert cwnd to an infinite value when switching > from BBR to another congestion control. > > This patch fixes it by disallowing such cwnd undo operation > upon switching congestion control. Note that undo_marker > is not reset s.t. the packets that were incorrectly marked > lost would be corrected. We only avoid undoing the cwnd in > tcp_undo_cwnd_reduction(). > > Signed-off-by: Yuchung Cheng <ych...@google.com> > Signed-off-by: Soheil Hassas Yeganeh <soh...@google.com> > Signed-off-by: Neal Cardwell <ncardw...@google.com> > Signed-off-by: Eric Dumazet <eduma...@google.com> Applied and queued up for -stable, thanks!
