* how to avoid CPU watchdog error during debug
@ 2021-08-25 1:06 ckim
2021-08-26 17:34 ` Philipp Hortmann
0 siblings, 1 reply; 4+ messages in thread
From: ckim @ 2021-08-25 1:06 UTC (permalink / raw)
To: kernelnewbies
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Hello,
While debugging a kernel module, I get this error and the OS crashes.
[39068.833652] rcu: INFO: rcu_sched self-detected stall on CPU
[39068.834739] watchdog: BUG: soft lockup - CPU#3 stuck for 164s!
[systemd-journal:399]
[39068.834854] watchdog: BUG: soft lockup - CPU#0 stuck for 164s!
[test_axpu_app:2896]
This seems because I stopped the processor for debugging.
How can I avoid this watchdog error during debug?
Any help will be appreciated. Thanks!
Chan Kim
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: how to avoid CPU watchdog error during debug
2021-08-25 1:06 how to avoid CPU watchdog error during debug ckim
@ 2021-08-26 17:34 ` Philipp Hortmann
2021-08-30 1:46 ` ckim
0 siblings, 1 reply; 4+ messages in thread
From: Philipp Hortmann @ 2021-08-26 17:34 UTC (permalink / raw)
To: kernelnewbies
On 8/25/21 3:06 AM, ckim@etri.re.kr wrote:
> Hello,
>
> While debugging a kernel module, I get this error and the OS crashes.
>
> [39068.833652] rcu: INFO: rcu_sched self-detected stall on CPU
>
> [39068.834739] watchdog: BUG: soft lockup - CPU#3 stuck for 164s!
> [systemd-journal:399]
>
> [39068.834854] watchdog: BUG: soft lockup - CPU#0 stuck for 164s!
> [test_axpu_app:2896]
>
> This seems because I stopped the processor for debugging.
>
> How can I avoid this watchdog error during debug?
>
> Any help will be appreciated. Thanks!
>
> Chan Kim
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
Hi Kim,
since many things are time depending in the kernel it is difficult to
stop parts of the kernel. The question is if it is really absolutely
necessary to do this? Why you can not do it by logging with printk?
Debugging is described in:
https://www.doc-developpement-durable.org/file/Projets-informatiques/cours-&-manuels-informatiques/Linux/Linux%20Kernel%20Development,%203rd%20Edition.pdf
See Chapter 18 Debugging
Thanks! Bye Philipp
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^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: how to avoid CPU watchdog error during debug
2021-08-26 17:34 ` Philipp Hortmann
@ 2021-08-30 1:46 ` ckim
2021-09-25 21:34 ` jim.cromie
0 siblings, 1 reply; 4+ messages in thread
From: ckim @ 2021-08-30 1:46 UTC (permalink / raw)
To: 'Philipp Hortmann', kernelnewbies
>
> since many things are time depending in the kernel it is difficult to stop
> parts of the kernel. The question is if it is really absolutely necessary
> to do this? Why you can not do it by logging with printk?
>
> Debugging is described in:
> https://www.doc-developpement-durable.org/file/Projets-
> informatiques/cours-&-manuels-
> informatiques/Linux/Linux%20Kernel%20Development,%203rd%20Edition.pdf
>
> See Chapter 18 Debugging
>
> Thanks! Bye Philipp
>
Hi, Philipp,
I've found your answer too late. Thanks for the info(I learned something
about the early_prink from the book).
Actually, shortly after I sent my question, I learned how to make printk
appear in the console (not in the dmesg buffer) and was using it.
(I added the line "kernel.prink = 5 4 1 7" in the /etc/sysctl.conf file.
So I've set the default console log level to 5 making default printk appear
in the console.)
Thanks!
Chan
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
_______________________________________________
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: how to avoid CPU watchdog error during debug
2021-08-30 1:46 ` ckim
@ 2021-09-25 21:34 ` jim.cromie
0 siblings, 0 replies; 4+ messages in thread
From: jim.cromie @ 2021-09-25 21:34 UTC (permalink / raw)
To: ckim; +Cc: Philipp Hortmann, kernelnewbies
On Sun, Aug 29, 2021 at 7:46 PM <ckim@etri.re.kr> wrote:
>
>
> >
> > since many things are time depending in the kernel it is difficult to stop
> > parts of the kernel. The question is if it is really absolutely necessary
> > to do this? Why you can not do it by logging with printk?
> >
> > Debugging is described in:
> > https://www.doc-developpement-durable.org/file/Projets-
> > informatiques/cours-&-manuels-
> > informatiques/Linux/Linux%20Kernel%20Development,%203rd%20Edition.pdf
> >
> > See Chapter 18 Debugging
> >
> > Thanks! Bye Philipp
> >
> Hi, Philipp,
> I've found your answer too late. Thanks for the info(I learned something
> about the early_prink from the book).
> Actually, shortly after I sent my question, I learned how to make printk
> appear in the console (not in the dmesg buffer) and was using it.
> (I added the line "kernel.prink = 5 4 1 7" in the /etc/sysctl.conf file.
> So I've set the default console log level to 5 making default printk appear
> in the console.)
> Thanks!
>
> Chan
thanks for the followup
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-08-25 1:06 how to avoid CPU watchdog error during debug ckim
2021-08-26 17:34 ` Philipp Hortmann
2021-08-30 1:46 ` ckim
2021-09-25 21:34 ` jim.cromie
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