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From:   Krishna Chaitanya <chaitanya.mgit@gmail.com>
Date:   Mon, 24 Aug 2020 15:33:57 +0530
Message-ID: <CABPxzYKvPwtQwxMfRcv9jT+d92ErhYGR91SKBH86T3Rd2QH9Qg@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 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).

So, I am back to my initial guess that the SDIO specific async_rx_work is
causing/aggravating this issue.