NOHZ tick-stop error with ath10k SDIO

[Thomas Gleixner]

Paul,

On Wed, Aug 18 2021 at 10:56, Paul E. McKenney wrote:
> On Wed, Aug 18, 2021 at 02:02:17PM -0300, Fabio Estevam wrote:
>> On Wed, Aug 18, 2021 at 1:29 PM Fabio Estevam <festevam at gmail.com> wrote:
>> > On Wed, Aug 18, 2021 at 12:43 PM Paul E. McKenney <paulmck at kernel.org> wrote:
>> >
>> > > I believe that you need this commit (and possibly some prerequsites):
>> > >
>> > > 47c218dcae65 ("tick/sched: Prevent false positive softirq pending warnings on RT")
>> > >
>> > > Adding Qais on CC for his thoughts.
>> >
>> > Thanks for the suggestion, but I am running 5.13.11, which already
>> > contains this commit.
>> >
>> > Any extra logs I should capture to help us understand the problem?
>> 
>> In case it helps, I followed your suggestion from:
>> https://lkml.org/lkml/2020/12/10/676
>> 
>> With the debug patch and suggested command line, I get the following log:
>> https://pastebin.com/raw/X96zKw7i
>
> And it turns out that I am also seeing it in v5.14-rc2, just a lot less
> frequently than earlier.  I have seen three instances of handler #02
> (NET_TX_SOFTIRQ?) over the past month or so while you are seeing handler
> #08 (BLOCK_SOFTIRQ?), in case that makes a difference.

Huch? #02 is TIMER_SOFTIRQ and #08 is NET_TX_SOFTIRQ.

And looking at that ftrace output in the pastebin there is nothing which
raises NET_TX_SOFTIRQ but then the warning claims it is pending.

This does not make any sense at all.

Thanks,

        tglx