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From: Tejun Heo <tj@kernel.org>
To: Li Jinlin <lijinlin3@huawei.com>
Cc: josef@toxicpanda.com, axboe@kernel.dk, cgroups@vger.kernel.org,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	liuzhiqiang26@huawei.com
Subject: Re: [PATCH v2] blk-iocost: fix shift-out-of-bounds in iocg_hick_delay()
Date: Mon, 28 Nov 2022 09:58:18 -1000	[thread overview]
Message-ID: <Y4US2vFmR4pnw08Z@slm.duckdns.org> (raw)
In-Reply-To: <20221128030413.882998-1-lijinlin3@huawei.com>

On Mon, Nov 28, 2022 at 11:04:13AM +0800, Li Jinlin wrote:
>  	/* calculate the current delay in effect - 1/2 every second */
>  	tdelta = now->now - iocg->delay_at;
>  	if (iocg->delay)
> -		delay = iocg->delay >> div64_u64(tdelta, USEC_PER_SEC);
> +		delay = iocg->delay >>
> +			min_t(u64, div64_u64(tdelta, USEC_PER_SEC), 63);

I replied earlier but the right thing to do here is setting delay to 0 if
the shift is >= 64.

Thanks.

-- 
tejun

  reply	other threads:[~2022-11-28 19:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-28  3:04 [PATCH v2] blk-iocost: fix shift-out-of-bounds in iocg_hick_delay() Li Jinlin
2022-11-28 19:58 ` Tejun Heo [this message]
2022-11-29  1:14   ` Yu Kuai
2022-11-29  2:49     ` Li Jinlin
2022-11-29  2:59       ` Yu Kuai
2022-11-29  4:52         ` Li Jinlin

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