* Kernel Panic sysrq questions
@ 2017-08-18 15:40 Sriram V
2017-09-18 22:35 ` Randy Dunlap
0 siblings, 1 reply; 3+ messages in thread
From: Sriram V @ 2017-08-18 15:40 UTC (permalink / raw)
To: linux-kernel
Hi,
1. I am testing my watchdog driver. The driver uses the internal
watchdog (Internal to SOC).
2. I use a single core SOC.
3. I have a workqueue which pets the watchdog every 60 seconds.
4. I trigger a kernel crash by doing a echo c > /proc/sysrq-trigger to
trigger a kernel crash
5. Even after the crash, I observe that the workqueue gets
periodically executed. (I have a printk
inside the workqueue before the pet as a result the watchdog does
not reset the board.
My Understanding is When a fatal panic happens, The Kernel is in
frozen state (no workques
or tasks get executed).
Is my understanding correct or am i missing something here.
Thanks,
Regards,
Sriram
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Kernel Panic sysrq questions
2017-08-18 15:40 Kernel Panic sysrq questions Sriram V
@ 2017-09-18 22:35 ` Randy Dunlap
2017-09-19 0:23 ` Tejun Heo
0 siblings, 1 reply; 3+ messages in thread
From: Randy Dunlap @ 2017-09-18 22:35 UTC (permalink / raw)
To: Sriram V, linux-kernel, Tejun Heo
On 08/18/17 08:40, Sriram V wrote:
> Hi,
>
> 1. I am testing my watchdog driver. The driver uses the internal
> watchdog (Internal to SOC).
> 2. I use a single core SOC.
> 3. I have a workqueue which pets the watchdog every 60 seconds.
> 4. I trigger a kernel crash by doing a echo c > /proc/sysrq-trigger to
> trigger a kernel crash
> 5. Even after the crash, I observe that the workqueue gets
> periodically executed. (I have a printk
> inside the workqueue before the pet as a result the watchdog does
> not reset the board.
>
> My Understanding is When a fatal panic happens, The Kernel is in
> frozen state (no workques
> or tasks get executed).
>
> Is my understanding correct or am i missing something here.
Hi,
What kernel version?
I don't see anything in the wq docs about that specific point.
Tejun?
--
~Randy
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Kernel Panic sysrq questions
2017-09-18 22:35 ` Randy Dunlap
@ 2017-09-19 0:23 ` Tejun Heo
0 siblings, 0 replies; 3+ messages in thread
From: Tejun Heo @ 2017-09-19 0:23 UTC (permalink / raw)
To: Randy Dunlap; +Cc: Sriram V, linux-kernel
Hello,
On Mon, Sep 18, 2017 at 03:35:36PM -0700, Randy Dunlap wrote:
> > My Understanding is When a fatal panic happens, The Kernel is in
> > frozen state (no workques
> > or tasks get executed).
> >
> > Is my understanding correct or am i missing something here.
>
> Hi,
> What kernel version?
>
> I don't see anything in the wq docs about that specific point.
There's nothing workqueue specific there. Panic doesn't bring the
system to a complete stop in general. If you wanna change how the
system behaves post-panic, please take a look at panic= boot param.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-09-19 0:23 UTC | newest]
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