linux-kernel - Re: [PATCH 2/2] usb: host: xhci: Handle the right timeout command

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Message-ID: <CAMz4kuKnTQtM243ke0VJgEOsqWbRnR9_BvsWXB-PcXndgQ8Vmg@mail.gmail.com>
Date:   Tue, 27 Dec 2016 11:07:26 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Mathias Nyman <mathias.nyman@...ux.intel.com>
Cc:     Lu Baolu <baolu.lu@...ux.intel.com>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        USB <linux-usb@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Mark Brown <broonie@...nel.org>,
        "Lu, Baolu" <baolu.lu@...el.com>
Subject: Re: [PATCH 2/2] usb: host: xhci: Handle the right timeout command

Hi,

On 21 December 2016 at 21:00, Mathias Nyman
<mathias.nyman@...ux.intel.com> wrote:
> On 21.12.2016 04:22, Baolin Wang wrote:
>>
>> Hi Mathias,
>>
>> On 20 December 2016 at 23:13, Mathias Nyman
>> <mathias.nyman@...ux.intel.com> wrote:
>>>
>>> On 20.12.2016 09:30, Baolin Wang wrote:
>>> ...
>>>
>>> Alright, I gathered all current work related to xhci races and timeouts
>>> and put them into a branch:
>>>
>>> git://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git
>>> timeout_race_fixes
>>>
>>> Its based on 4.9
>>> It includes a few other patches just to avoid conflicts and  make my life
>>> easier
>>>
>>> Interesting patches are:
>>>
>>> ee4eb91 xhci: remove unnecessary check for pending timer
>>> 0cba67d xhci: detect stop endpoint race using pending timer instead of
>>> counter.
>>> 4f2535f xhci: Handle command completion and timeout race
>>> b9d00d7 usb: host: xhci: Fix possible wild pointer when handling abort
>>> command
>>> 529a5a0 usb: xhci: fix possible wild pointer
>>> 4766555 xhci: Fix race related to abort operation
>>> de834a3 xhci: Use delayed_work instead of timer for command timeout
>>> 69973b8 Linux 4.9
>>>
>>> The fixes for command queue races will go to usb-linus and stable, the
>>> reworks for stop ep watchdog timer will go to usb-next.
>>
>>
>> How about applying below patch in your 'timeout_race_fixes' branch?
>> [PATCH] usb: host: xhci: Clean up commands when stop endpoint command is
>> timeout
>> https://lkml.org/lkml/2016/12/13/94
>>
>
> usb_hc_died() should eventyally end up calling xhci_mem_cleanup()
> which will cleanup the command queue. But I need to look into that

usb_hc_died() did not call xhci_mem_cleanup() to clean up command
queue, it just disconnects all children devices attached on the dying
hub. I did not find where it will clean up the command queue when
issuing usb_hc_died(). Also before issuing usb_hc_died() in
xhci_handle_command_timeout(), we will call
xhci_cleanup_command_queue(). I think it should same as in
xhci_stop_endpoint_command_watchdog().

-- 
Baolin.wang
Best Regards