BugLink: https://bugs.launchpad.net/bugs/1845405

[ Upstream commit d4d6ec6d ]

In case of TCA_HHF_NON_HH_WEIGHT or TCA_HHF_QUANTUM is zero,
it would make no progress inside the loop in hhf_dequeue() thus
kernel would get stuck.

Fix this by checking this corner case in hhf_change().

Fixes: 10239edf ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Reported-by: syzbot+bc6297c11f19ee807dc2@syzkaller.appspotmail.com
Reported-by: syzbot+041483004a7f45f1f20a@syzkaller.appspotmail.com
Reported-by: syzbot+55be5f513bed37fc4367@syzkaller.appspotmail.com
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Terry Lam <vtlam@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>