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Date:   Thu, 02 Jan 2020 16:35:07 -0800 (PST)
Message-Id: <20200102.163507.404343273086201773.davem@davemloft.net>
To:     wenyang@linux.alibaba.com
Cc:     toke@toke.dk, ldir@darbyshire-bryant.me.uk, toke@redhat.com,
        xiyou.wangcong@gmail.com, cake@lists.bufferbloat.net,
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Subject: Re: [PATCH] sch_cake: avoid possible divide by zero in
 cake_enqueue()
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20200102092143.8971-1-wenyang@linux.alibaba.com>
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From: Wen Yang <wenyang@linux.alibaba.com>
Date: Thu,  2 Jan 2020 17:21:43 +0800

> 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>

Applied and queued up for -stable.