wake_up_interruptible in ISR

[Jeff Haran]

> -----Original Message-----
> From: kernelnewbies-bounces at kernelnewbies.org [mailto:kernelnewbies-
> bounces at kernelnewbies.org] On Behalf Of Chan Kim
> Sent: Monday, May 25, 2015 10:23 PM
> To: kernelnewbies at kernelnewbies.org
> Subject: wake_up_interruptible in ISR
> 
> 
> 
> Hello,
> 
> I see in the source (linux ver 3.3) that wake_up_interruptible function
> doesn't sleep 

Not sure how you came to that conclusion, but calling that function definitely can result in an attempt
to do a context switch. That's what the "scheduling while atomic" is telling you.
To my knowledge it is only safe to call this from process context.

No ISRs, no bottom halves.

Could be it's that "_interruptible" in the name that is misleading you. That means the wait can be
interrupted and the call can return if the process doing the waiting is delivered a signal. It's got
nothing to do with "interrupts" per se.

Jeff Haran

> so I used in it an ISR but I'm getting 'BUG:scheduling while
> atomic' message. (I'm not sure it's coming from this) I'm looking for the exact
> cause but Is there any caveat when using wake_up_interruptible() in an ISR?
> (I found some drivers use it in ISR, some use it in work_struct)
> 
> I also read in http://www.slideshare.net/rampalliraj/tasklet-vs-work-
> queues?from_action=save  that tasklet is not allowed to sleep but work is.
> (because  tasklet is not in process context, but in bottom-half) I don't know if
> I have to move my wake_up_interruptible function to tasklet or
> work(queue) or even it matters to the current problem.
> 
> Any tip will be appreciated.
> Regards,
> 
> Chan
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