On Mon, Jan 30, 2017 at 2:23 PM, Eric Dumazet [off-list ref] wrote:

On Mon, Jan 30, 2017 at 2:09 PM, Dimitris Michailidis
[off-list ref] wrote:

quoted

ip6_make_flowlabel() determines the flow label for IPv6 packets. It's
supposed to be passed a flow label, which it returns as is if non-0 and
in some other cases, otherwise it calculates a new value.

The problem is callers often pass a flowi6.flowlabel, which may also
contain traffic class bits.

Do you have an idea which commit added this bug Dimitris ?

[Resending reply as text]

I believe it was wrong since cb1ce2ef387b01 ("ipv6: Implement
automatic flow label generation on transmit"), the commit that
introduced ip6_make_flowlabel(). The function was somewhat different
at the time but it was doing

       if (!flowlabel && (autolabel || net->ipv6.sysctl.auto_flowlabels)) {
       ...
       }
       return flowlabel;

 and all the callers were passing flowi6.flowlabel.