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From: jianchao.w.wang@oracle.com (jianchao.wang)
Subject: [PATCH V5 2/2] nvme-pci: fixup the timeout case when reset is ongoing
Date: Fri, 19 Jan 2018 14:53:37 +0800	[thread overview]
Message-ID: <23b3ea15-aed0-3b2f-e02f-124fe6fdf618@oracle.com> (raw)
In-Reply-To: <20180119060521.GD12043@localhost.localdomain>

Hi Keith

Thanks for your kindly reminding.

On 01/19/2018 02:05 PM, Keith Busch wrote:
>>> The driver may be giving up on the command here, but that doesn't mean
>>> the controller has. We can't just end the request like this because that
>>> will release the memory the controller still owns. We must wait until
>>> after nvme_dev_disable clears bus master because we can't say for sure
>>> the controller isn't going to write to that address right after we end
>>> the request.
>>>
>> Yes, but the controller is going to be reseted or shutdown at the moment,
>> even if the controller accesses a bad address and goes wrong, everything will
>> be ok after reset or shutdown. :)
> Hm, I don't follow. DMA access after free is never okay.
Yes, this may cause unexpected memory corruption.

Thanks
Jianchao

  reply	other threads:[~2018-01-19  6:53 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-18 10:10 [PATCH V5 0/2] nvme-pci: fix the timeout case when reset is ongoing Jianchao Wang
2018-01-18 10:10 ` [PATCH V5 1/2] nvme-pci: introduce RECONNECTING state to mark initializing procedure Jianchao Wang
2018-01-18 10:17   ` Max Gurtovoy
2018-01-19  9:49     ` jianchao.wang
2018-01-18 15:23   ` James Smart
2018-01-18 10:10 ` [PATCH V5 2/2] nvme-pci: fixup the timeout case when reset is ongoing Jianchao Wang
2018-01-19  4:59   ` Keith Busch
2018-01-19  5:55     ` jianchao.wang
2018-01-19  6:05       ` Keith Busch
2018-01-19  6:53         ` jianchao.wang [this message]
2018-01-18 15:34 ` [PATCH V5 0/2] nvme-pci: fix " James Smart
2018-01-19  8:01 ` Keith Busch
2018-01-19  8:14   ` jianchao.wang
2018-01-19  8:42     ` Keith Busch
2018-01-19  9:02       ` jianchao.wang
2018-01-19 11:52         ` Keith Busch
2018-01-19 13:56           ` jianchao.wang
2018-01-20  2:11             ` Keith Busch
2018-01-20 14:07               ` jianchao.wang
2018-01-20 14:14                 ` jianchao.wang

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