From: "Alex G." <mr.nuke.me@gmail.com>
To: okaya@codeaurora.org
Cc: Alex_Gagniuc@dellteam.com, linux-pci@vger.kernel.org,
shyam_iyer@dell.com, linux-nvme@lists.infradead.org,
Keith Busch <keith.busch@intel.com>,
austin_bolen@dell.com, linux-pci-owner@vger.kernel.org
Subject: Re: AER: Malformed TLP recovery deadlock with NVMe drives
Date: Mon, 7 May 2018 15:16:02 -0500 [thread overview]
Message-ID: <5c97a7c2-cb53-4740-fda0-50ba92288c5c@gmail.com> (raw)
In-Reply-To: <7afd280ad80a73b39e6c9b9a9e29abcc@codeaurora.org>
On 05/07/2018 01:46 PM, okaya@codeaurora.org wrote:
> On 2018-05-07 19:36, Alex G. wrote:
>> Hi! Me again!
>>
>> I'm seeing what appears to be a deadlock in the AER recovery path. It
>> seems that the device_lock() call in report_slot_reset() never returns.
>> How we get there is interesting:
>
> Can you give this patch a try?
>
Oh! Patches so soon? Yay!
> https://patchwork.kernel.org/patch/10351515/
Thank you! I tried a few runs. there was one run where we didn't lock
up, but the other runs all went like before.
For comparison, the run that didn't deadlock looked like [2].
Alex
[2] http://gtech.myftp.org/~mrnuke/nvme_logs/log-20180507-1429.log
>> Injection of the error happens by changing the maximum payload size to
>> 128 bytes from 256. This is on the switch upstream port.
>> When there's IO to the drive, switch sees a malformed TLP. Switch
>> reports error, AER handles it.
>> More IO goes, another error is triggered, and this time the root port
>> reports it. AER recovery hits the NVMe drive behind the affetced
>> upstream port and deadlocks.
>>
>> I've added some printks in the AER handler to see which lock dies, and I
>> have a fairly succinct log[1], also pasted below. It appears somebody is
>> already holding the lock to the PCI device behind the sick upstream
>> port, and never releases it.
>>
>>
>> I'm not sure how to track down other users of the lock, and I"m hoping
>> somebody may have a brighter idea.
>>
>> Alex
>>
>>
>> [1] http://gtech.myftp.org/~mrnuke/nvme_logs/log-20180507-1308.log
>>
``
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WARNING: multiple messages have this Message-ID (diff)
From: mr.nuke.me@gmail.com (Alex G.)
Subject: AER: Malformed TLP recovery deadlock with NVMe drives
Date: Mon, 7 May 2018 15:16:02 -0500 [thread overview]
Message-ID: <5c97a7c2-cb53-4740-fda0-50ba92288c5c@gmail.com> (raw)
In-Reply-To: <7afd280ad80a73b39e6c9b9a9e29abcc@codeaurora.org>
On 05/07/2018 01:46 PM, okaya@codeaurora.org wrote:
> On 2018-05-07 19:36, Alex G. wrote:
>> Hi! Me again!
>>
>> I'm seeing what appears to be a deadlock in the AER recovery path. It
>> seems that the device_lock() call in report_slot_reset() never returns.
>> How we get there is interesting:
>
> Can you give this patch a try?
>
Oh! Patches so soon? Yay!
> https://patchwork.kernel.org/patch/10351515/
Thank you! I tried a few runs. there was one run where we didn't lock
up, but the other runs all went like before.
For comparison, the run that didn't deadlock looked like [2].
Alex
[2] http://gtech.myftp.org/~mrnuke/nvme_logs/log-20180507-1429.log
>> Injection of the error happens by changing the maximum payload size to
>> 128 bytes from 256. This is on the switch upstream port.
>> When there's IO to the drive, switch sees a malformed TLP. Switch
>> reports error, AER handles it.
>> More IO goes, another error is triggered, and this time the root port
>> reports it. AER recovery hits the NVMe drive behind the affetced
>> upstream port and deadlocks.
>>
>> I've added some printks in the AER handler to see which lock dies, and I
>> have a fairly succinct log[1], also pasted below. It appears somebody is
>> already holding the lock to the PCI device behind the sick upstream
>> port, and never releases it.
>>
>>
>> I'm not sure how to track down other users of the lock, and I"m hoping
>> somebody may have a brighter idea.
>>
>> Alex
>>
>>
>> [1] http://gtech.myftp.org/~mrnuke/nvme_logs/log-20180507-1308.log
>>
``
next prev parent reply other threads:[~2018-05-07 20:16 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-07 18:36 AER: Malformed TLP recovery deadlock with NVMe drives Alex G.
2018-05-07 18:36 ` Alex G.
2018-05-07 18:46 ` okaya
2018-05-07 18:46 ` okaya
2018-05-07 20:16 ` Alex G. [this message]
2018-05-07 20:16 ` Alex G.
2018-05-07 20:30 ` okaya
2018-05-07 20:30 ` okaya
2018-05-07 20:58 ` Alex G.
2018-05-07 20:58 ` Alex G.
2018-05-07 21:48 ` Sinan Kaya
2018-05-07 21:48 ` Sinan Kaya
2018-05-07 22:45 ` okaya
2018-05-07 22:45 ` okaya
2018-05-07 23:57 ` Alex_Gagniuc
2018-05-07 23:57 ` Alex_Gagniuc
2018-05-08 0:21 ` okaya
2018-05-08 0:21 ` okaya
2018-05-08 16:58 ` Bjorn Helgaas
2018-05-08 16:58 ` Bjorn Helgaas
2018-05-08 17:32 ` Alex G.
2018-05-08 17:32 ` Alex G.
2018-05-08 18:01 ` Bjorn Helgaas
2018-05-08 18:01 ` Bjorn Helgaas
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