We have observed meters working unexpected if traffic is 3+Gbit/s
with multiple connections.
now_ms is not pretected by meter->lock, we may get a negative
long_delta_ms when another cpu updated meter->used, then:
delta_ms = (u32)long_delta_ms;
which will be a large value.
band->bucket += delta_ms * band->rate;
then we get a wrong band->bucket.
OpenVswitch userspace datapath has fixed the same issue[1] some
time ago, and we port the implementation to kernel datapath.
[1] https://patchwork.ozlabs.org/project/openvswitch/patch/20191025114436.9746-1-i.maximets@ovn.org/
Fixes: 96fbc13d7e ("openvswitch: Add meter infrastructure")
Signed-off-by: Tao Liu <thomas.liu@ucloud.cn>
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
e4df1b0c24