Re: [PATCH 0/3] Fix USB deadlock caused by SCSI error handling

[Hannes Reinecke <hare@suse.de>]

On 04/10/2014 05:31 PM, Alan Stern wrote:
> On Thu, 10 Apr 2014, Hannes Reinecke wrote:
>
>> On 04/10/2014 12:58 PM, Andreas Reis wrote:
>>> That patch appears to work in preventing the crashes, judged on one
>>> repeated appearance of the bug.
>>>
>>> dmesg had the usual
>>> [  215.229903] usb 4-2: usb_disable_lpm called, do nothing
>>> [  215.336941] usb 4-2: reset SuperSpeed USB device number 3 using
>>> xhci_hcd
>>> [  215.350296] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called
>>> with disabled ep ffff880427b829c0
>>> [  215.350305] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called
>>> with disabled ep ffff880427b82a08
>>> [  215.350621] usb 4-2: usb_enable_lpm called, do nothing
>>>
>>> repeated five times, followed by one
>>> [  282.795801] sd 8:0:0:0: Device offlined - not ready after error
>>> recovery
>>>
>>> and then as often as something tried to read from it:
>>> [  295.585472] sd 8:0:0:0: rejecting I/O to offline device
>>>
>>> The stick could then be properly un- and remounted (the latter if it
>>> had been physically replugged) without issue � for the bug to
>>> reoccur after one to three minutes. I tried this three times, no
>>> dmesg difference except the ep addresses varied on two of that.
>>>
>> Was this just that patch you've tested with or the entire patch series?
>>
>> If the latter, Alan, is this the expected outcome?
>
> Yes, it is.  The same thing should happen with the entire patch series.
>
>> I would've thought the error recover should _not_ run into
>> offlining devices here, but rather the device should be recovered
>> eventually.
>
> The command times out, it is aborted, and the command is retried.  The
> same thing happens, and we repeat five times.  Eventually the SCSI core
> gives up and declares the device to be offline.
>
Hmm. Ok. If you are fine with it who am I to argue here.
James, shall I resent the patch series?

Cheers,

Hannes

-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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