From: Yuchung Cheng
Date: Wed, 6 Jan 2016 12:42:38 -0800
> Patch 3759824da87b ("tcp: PRR uses CRB mode by default and SS mode
> conditionally") introduced a bug that cwnd may become 0 when both
> inflight and sndcnt are 0 (cwnd = inflight + sndcnt). This may lead
> to a div-by-zero if the connec
Patch 3759824da87b ("tcp: PRR uses CRB mode by default and SS mode
conditionally") introduced a bug that cwnd may become 0 when both
inflight and sndcnt are 0 (cwnd = inflight + sndcnt). This may lead
to a div-by-zero if the connection starts another cwnd reduction
phase by setting tp->prior_cwnd t
