Re: [PATCH] sch_cake: avoid possible divide by zero in cake_enqueue()

From: Toke HÃiland-JÃrgensen
Date: Thu Jan 02 2020 - 18:43:12 EST


Wen Yang <wenyang@xxxxxxxxxxxxxxxxx> writes:

> 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@xxxxxxxxxxxxxxxxx>
> Cc: Kevin Darbyshire-Bryant <ldir@xxxxxxxxxxxxxxxxxxxxxxx>
> Cc: Toke HÃiland-JÃrgensen <toke@xxxxxxxxxx>
> Cc: David S. Miller <davem@xxxxxxxxxxxxx>
> Cc: Cong Wang <xiyou.wangcong@xxxxxxxxx>
> Cc: cake@xxxxxxxxxxxxxxxxxxxxx
> Cc: netdev@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx

Acked-by: Toke HÃiland-JÃrgensen <toke@xxxxxxx>