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Sender: Guenter Roeck <groeck7@gmail.com>
Date: Sun, 14 Apr 2024 14:18:03 -0700
From: Guenter Roeck <linux@roeck-us.net>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org, patches@lists.linux.dev,
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Subject: Re: [PATCH 5.10 000/294] 5.10.215-rc1 review
Message-ID: <039f041e-ca03-4750-8d69-87aef0ad1752@roeck-us.net>
References: <20240411095435.633465671@linuxfoundation.org>
 <9ac4f94c-414e-4c12-bfe0-36aff3e318bc@roeck-us.net>
 <2024041411-stencil-unscathed-bc65@gregkh>
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In-Reply-To: <2024041411-stencil-unscathed-bc65@gregkh>

Hi Greg,

On Sun, Apr 14, 2024 at 08:09:39AM +0200, Greg Kroah-Hartman wrote:
> On Sat, Apr 13, 2024 at 07:11:57AM -0700, Guenter Roeck wrote:
> > Hi,
> > 
> > On Thu, Apr 11, 2024 at 11:52:43AM +0200, Greg Kroah-Hartman wrote:
> > > This is the start of the stable review cycle for the 5.10.215 release.
> > > There are 294 patches in this series, all will be posted as a response
> > > to this one.  If anyone has any issues with these being applied, please
> > > let me know.
> > > 
> > > Responses should be made by Sat, 13 Apr 2024 09:53:55 +0000.
> > > Anything received after that time might be too late.
> > > 
> > > The whole patch series can be found in one patch at:
> > > 	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.10.215-rc1.gz
> > > or in the git tree and branch at:
> > > 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y
> > > and the diffstat can be found below.
> > > 
> > > thanks,
> > > 
> > > greg k-h
> > > 
> > > -------------
> > [ ... ]
> > > 
> > > Oliver Neukum <oneukum@suse.com>
> > >     usb: cdc-wdm: close race between read and workqueue
> > > 
> > 
> > Just in case it has not been reported yet:
> > 
> > This patch is causing connection failures (timeouts) on all
> > Chromebooks using the cdc-wdm driver for cellular modems, with
> > all kernel branches where this patch has been applied.
> > Reverting it fixes the problem.
> > 
> > I am copying some of the Google employees involved in identifying
> > the regression in case additional feedback is needed.
> 
> Can you all respond to Oliver on the linux-usb list where this was
> originally submitted to work it out?  This commit has been in the tree
> for almost a month now with no reported problems that I can see.
> 

Who knows, maybe only a certain type of usb cellular modems using cdc-wdm
is affected. Either case, the problem was found less than two days after
the stable tree merges into ChromeOS, and it took only about a week from
there to identify the offending patch. I think that was actually an amazing
job, given the size of those merges and because the failure is not absolute
but results in unreliable tests due to timeouts.

Anyway, sure, we'll get in touch with Oliver. Other than that, please take
this report as a heads-up in case anyone else reports similar problems.

Thanks,
Guenter