From: Wen Yang Date: Thu, 2 Jan 2020 09:21:43 +0000 (+0800) Subject: sch_cake: avoid possible divide by zero in cake_enqueue() X-Git-Tag: v5.15~4789^2~38 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=68aab823c223646fab311f8a6581994facee66a0;p=mirror_ubuntu-kernels.git sch_cake: avoid possible divide by zero in cake_enqueue() 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 Cc: Kevin Darbyshire-Bryant Cc: Toke Høiland-Jørgensen Cc: David S. Miller Cc: Cong Wang Cc: cake@lists.bufferbloat.net Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller --- diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c index e0f40400f679..2277369feae5 100644 --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -1769,7 +1769,7 @@ 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);