Re: [PATCH] wireless: ath10k: Return early in ath10k_qmi_event_server_exit() to avoid hard crash on reboot

From: Sibi Sankar <sibis@codeaurora.org>
To: govinds@codeaurora.org
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Brian Norris <briannorris@chromium.org>,
	John Stultz <john.stultz@linaro.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Rakesh Pillai <pillair@qti.qualcomm.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Niklas Cassel <niklas.cassel@linaro.org>,
	Amit Pundir <amit.pundir@linaro.org>,
	Kalle Valo <kvalo@codeaurora.org>,
	ath10k <ath10k@lists.infradead.org>,
	linux-kernel-owner@vger.kernel.org
Subject: Re: [PATCH] wireless: ath10k: Return early in ath10k_qmi_event_server_exit() to avoid hard crash on reboot
Date: Thu, 04 Jun 2020 23:47:18 +0530	[thread overview]
Message-ID: <40a7d87e5774d56d9ca31e4de0c17831@codeaurora.org> (raw)
In-Reply-To: <4e0642b9882c41f4c10963b265bf6d9f@codeaurora.org>

On 2020-06-03 15:37, govinds@codeaurora.org wrote:
> Hi Mani,
> 
> On 2020-06-03 05:57, Manivannan Sadhasivam wrote:
>> On Tue, Jun 02, 2020 at 01:04:26PM -0700, Brian Norris wrote:
>>> On Tue, Jun 2, 2020 at 12:40 PM John Stultz <john.stultz@linaro.org> 
>>> wrote:
>>> > On Tue, Jun 2, 2020 at 12:16 PM Brian Norris <briannorris@chromium.org> wrote:
>>> > > On Mon, Jun 1, 2020 at 10:25 PM John Stultz <john.stultz@linaro.org> wrote:
>>> > > >
>>> > > > Ever since 5.7-rc1, if we call
>>> > > > ath10k_qmi_remove_msa_permission(), the db845c hard crashes on
>>> > > > reboot, resulting in the device getting stuck in the usb crash
>>> > > > debug mode and not coming back up wihthout a hard power off.
>>> > > >
>>> > > > This hack avoids the issue by returning early in
>>> > > > ath10k_qmi_event_server_exit().
>>> > > >
>>> > > > A better solution is very much desired!
>>> > >
>>> > > Any chance you can bisect what caused this? There are a lot of
>>> > > non-ath10k pieces involved in this stuff.
>>> >
>>> > Amit had spent some work on chasing it down to the in kernel qrtr-ns
>>> > work, and reported it here:
>>> >   https://lists.infradead.org/pipermail/ath10k/2020-April/014970.html
>>> >
>>> > But that discussion seemingly stalled out, so I came up with this hack
>>> > to workaround it for us.
>>> 
>>> If I'm reading it right, then that means we should revert this stuff
>>> from v5.7-rc1:
>>> 
>>> 0c2204a4ad71 net: qrtr: Migrate nameservice to kernel from userspace
>>> 
>>> At least, until people can resolve the tail end of that thread. New
>>> features (ath11k, etc.) are not a reason to break existing features
>>> (ath10k/wcn3990).
>> 
>> I don't agree with this. If you read through the replies to the bug 
>> report,
>> it is clear that NS migration uncovered a corner case or even a bug. 
>> So we
>> should try to fix that indeed.
>> 
>> Govind: Did you get chance to work on fixing this issue?
>> 
> 
> I have done basic testing by moving msa map/unmap from qmi service
> callbacks to init/de-init path.
> I will send patch for review.
> Reason for del_server needs to investigated from rproc side.

Govind,
On receiving SIGTERM, rmtfs would try
to perform a graceful shutdown of the
modem, that should be the source of
the del_server.

> 
>> Thanks,
>> Mani
>> 
>>> 
>>> Brian
> 
> Thanks,
> Govind

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