2014-07-30 19:31:08

by Joseph Salisbury

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Subject: [REVERT][v3.16-rc7][STABLE] usb: xhci: Prefer endpoint context dequeue pointer over stopped_trb

Hello,

A bug report was opened against Ubuntu[0]. After a kernel bisect, it
was found that reverting the following commit resolved this bug:

commit 1f81b6d22a5980955b01e08cf27fb745dc9b686f
Author: Julius Werner <[email protected]>
Date: Fri Apr 25 19:20:13 2014 +0300

usb: xhci: Prefer endpoint context dequeue pointer over stopped_trb

Please consider reverting commit SHA1 in the next mainline release as
well as the affected stable releases. It was included upstream as of
v3.15-rc3.

An upstream bug report can be found at:
https://bugzilla.kernel.org/show_bug.cgi?id=75521


Julius, I was hoping to get your feedback, since you are the patch
author. Do you think gathering any additional data will help diagnose
this issue, or would it be best to continue with this revert request?

Sincerely,

Joseph Salisbury


[0] http://pad.lv/1350480


2014-07-30 22:42:30

by Julius Werner

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Subject: Re: [REVERT][v3.16-rc7][STABLE] usb: xhci: Prefer endpoint context dequeue pointer over stopped_trb

Hi Joseph,

> Julius, I was hoping to get your feedback, since you are the patch
> author. Do you think gathering any additional data will help diagnose
> this issue, or would it be best to continue with this revert request?

As I understand it, this crash will disappear with Mathias' new rework
for finding the cycle state bit in
http://www.spinics.net/lists/linux-usb/msg111259.html , so a revert
should not be necessary.

2014-07-31 01:40:38

by Joseph Salisbury

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Subject: Re: [REVERT][v3.16-rc7][STABLE] usb: xhci: Prefer endpoint context dequeue pointer over stopped_trb

On 07/30/2014 06:42 PM, Julius Werner wrote:
> Hi Joseph,
>
>> Julius, I was hoping to get your feedback, since you are the patch
>> author. Do you think gathering any additional data will help diagnose
>> this issue, or would it be best to continue with this revert request?
> As I understand it, this crash will disappear with Mathias' new rework
> for finding the cycle state bit in
> http://www.spinics.net/lists/linux-usb/msg111259.html , so a revert
> should not be necessary.
Thanks, Julius. We will test that patch and report back.

Thanks,

Joe

2014-07-31 03:22:18

by Joseph Salisbury

[permalink] [raw]
Subject: Re: [REVERT][v3.16-rc7][STABLE] usb: xhci: Prefer endpoint context dequeue pointer over stopped_trb

On 07/30/2014 06:42 PM, Julius Werner wrote:
> Hi Joseph,
>
>> Julius, I was hoping to get your feedback, since you are the patch
>> author. Do you think gathering any additional data will help diagnose
>> this issue, or would it be best to continue with this revert request?
> As I understand it, this crash will disappear with Mathias' new rework
> for finding the cycle state bit in
> http://www.spinics.net/lists/linux-usb/msg111259.html , so a revert
> should not be necessary.
Hi Julius / Mathias,

I was able to built a test kernel with the patch against 3.16-rc7.
However, the patch would not compile against the 3.13.y stable tree(I'll
debug why further). Is there plans for a version of the patch that will
work with stable kernels?

Thanks,

Joe