From: Wen Yang wenyang@linux.alibaba.com
[ Upstream commit 68aab823c223646fab311f8a6581994facee66a0 ]
The variables 'window_interval' is u64 and do_div() truncates it to 32 bits, which means it can test non-zero and be truncated to zero for division. The unit of window_interval is nanoseconds, so its lower 32-bit is relatively easy to exceed. Fix this issue by using div64_u64() instead.
Fixes: 7298de9cd725 ("sch_cake: Add ingress mode") Signed-off-by: Wen Yang wenyang@linux.alibaba.com Cc: Kevin Darbyshire-Bryant ldir@darbyshire-bryant.me.uk Cc: Toke Høiland-Jørgensen toke@redhat.com Cc: David S. Miller davem@davemloft.net Cc: Cong Wang xiyou.wangcong@gmail.com Cc: cake@lists.bufferbloat.net Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Toke Høiland-Jørgensen toke@toke.dk Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/sched/sch_cake.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c index e4cf72b..824e3c3 100644 --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -1758,7 +1758,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch, q->avg_window_begin)); u64 b = q->avg_window_bytes * (u64)NSEC_PER_SEC;
- do_div(b, window_interval); + b = div64_u64(b, window_interval); q->avg_peak_bandwidth = cake_ewma(q->avg_peak_bandwidth, b, b > q->avg_peak_bandwidth ? 2 : 8);