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From: Coly Li <colyli@suse.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org,
	Ken Raeburn <raeburn@redhat.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH 1/2] bcache: avoid nr_stripes overflow in bcache_device_init()
Date: Mon, 13 Jul 2020 11:34:56 +0800	[thread overview]
Message-ID: <789e0fff-5fc3-1d2a-3e7a-62a4eac4ae59@suse.de> (raw)
In-Reply-To: <010a5d09-5de8-8f1e-4ff5-3f194f899073@kernel.dk>

On 2020/7/13 04:37, Jens Axboe wrote:
> On 7/12/20 11:47 AM, Coly Li wrote:
>> For some block devices which large capacity (e.g. 8TB) but small io_opt
>> size (e.g. 8 sectors), in bcache_device_init() the stripes number calcu-
>> lated by,
>> 	DIV_ROUND_UP_ULL(sectors, d->stripe_size);
>> might be overflow to the unsigned int bcache_device->nr_stripes.
>>
>> This patch uses an unsigned long variable to store DIV_ROUND_UP_ULL()
>> and after the value is checked to be available in unsigned int range,
>> sets it to bache_device->nr_stripes. Then the overflow is avoided.
> 
> Does that work on 32-bit, where sizeof(unsigned long) == 4?
> 

I will post v2 to explicit use uint64_t. Thanks for the remind.

Coly Li

  reply	other threads:[~2020-07-13  3:35 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-12 17:47 [PATCH 1/2] bcache: avoid nr_stripes overflow in bcache_device_init() Coly Li
2020-07-12 17:47 ` [PATCH 2/2] bcche: fix overflow in offset_to_stripe() Coly Li
2020-07-17 17:08   ` Sasha Levin
2020-07-12 17:49 ` [PATCH 1/2] bcache: avoid nr_stripes overflow in bcache_device_init() Coly Li
2020-07-12 20:38   ` Ken Raeburn
2020-07-13  3:35     ` Coly Li
2020-07-12 20:37 ` Jens Axboe
2020-07-13  3:34   ` Coly Li [this message]
2020-07-17 17:08 ` Sasha Levin

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