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From:   Krishna Chaitanya <chaitanya.mgit@gmail.com>
Date:   Mon, 24 Aug 2020 16:45:54 +0530
Message-ID: <CABPxzY+Fc22ke1ygRnDs0Uds0a7n=792QN8ALXciDrnx9SQuqQ@mail.gmail.com>
Subject: Re: [PATCH v2] ath10k: add flag to protect napi operation to avoid
 dead loop hang for SDIO
To:     Wen Gong <wgong@codeaurora.org>
Cc:     ath10k <ath10k@lists.infradead.org>,
        linux-wireless <linux-wireless@vger.kernel.org>
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On Mon, Aug 24, 2020 at 4:15 PM Wen Gong <wgong@codeaurora.org> wrote:
>
> On 2020-08-24 18:03, Krishna Chaitanya wrote:
> > On Mon, Aug 24, 2020 at 3:10 PM Wen Gong <wgong@codeaurora.org> wrote:
> >>
> >> On 2020-08-24 16:35, Krishna Chaitanya wrote:
> >> > On Mon, Aug 24, 2020 at 10:03 AM Wen Gong <wgong@codeaurora.org> wrote:
> >> >>
> >> >> It happened "Kernel panic - not syncing: hung_task: blocked tasks"
> >> >> when
> >> >> test simulate crash and ifconfig down/rmmod meanwhile.
> >> >>
> >> ...
> >> >>
> >> >>  #ifdef CONFIG_PM
> >> > Even though your DUT is SDIO based we should be doing this in general
> >> > for all, no?
> >> > core_restart + hif_stop is common to all.
> >> this patch does not have core_restart.
> > I was referring to the combination which is causing the issue.
> >
> >> I dit not hit the issue for others bus(PCIe,SNOC...), so I can not
> >> change them with a
> >> assumption they also have this issue.
> > But that doesn't make sense, the combination is being hit for others
> > also.
> > (they should also endup calling napi_disable twice?) or they are using
> > some other check to avoid this (doesn't appear so from a quick look at
> > the
> > code).
> Because I only use SDIO, I did not use others BUS, so I did not hit the
> issue
> on other BUS.
I understand, my point was based on the description the issue looks independent
of the BUS type, so, the fix should also be generic. I understand that
your testing
is only focused on SDIO, but we should have a generic fix and probably use
communities help to get it tested rather than fixing SDIO only.
> >
> > So, I am back to my initial guess that the SDIO specific async_rx_work
> > is
> > causing/aggravating this issue.
> the commit log of this patch has explain the reason, it is not caused by
> the
> async_rx_work and I have started the "ath10k: cancel rx worker in
> hif_stop for SDIO"
> for async_rx_work.
Sure.