tcp_bbr: remove sk_pacing_rate=0 transient during init
authorNeal Cardwell <ncardwell@google.com>
Fri, 14 Jul 2017 21:49:24 +0000 (17:49 -0400)
committerDavid S. Miller <davem@davemloft.net>
Sat, 15 Jul 2017 21:43:29 +0000 (14:43 -0700)
commit1d3648eb5d1fe9ed3d095ed8fa19ad11ca4c8bc0
tree1383cf659bf210514b73ce560294e2a1fe8ee1c2
parent79135b89b8af304456bd67916b80116ddf03d7b6
tcp_bbr: remove sk_pacing_rate=0 transient during init

Fix a corner case noticed by Eric Dumazet, where BBR's setting
sk->sk_pacing_rate to 0 during initialization could theoretically
cause packets in the sending host to hang if there were packets "in
flight" in the pacing infrastructure at the time the BBR congestion
control state is initialized. This could occur if the pacing
infrastructure happened to race with bbr_init() in a way such that the
pacer read the 0 rather than the immediately following non-zero pacing
rate.

Fixes: 0f8782ea1497 ("tcp_bbr: add BBR congestion control")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp_bbr.c