Sleeping after preempt_disable() possible?

Can I sleep after a call to preempt_disable() ?

Thanks,

Rick
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Re: Sleeping after preempt_disable() possible?

> Can I sleep after a call to preempt_disable() ?

What are you trying to do? You can sleep from process context. If two
different process context can access to shared data, you can use semaphore...


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Bora SAHIN
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Re: Sleeping after preempt_disable() possible?

>
> > Can I sleep after a call to preempt_disable() ?
>
> What are you trying to do? You can sleep from process context. If two
> different process context can access to shared data, you can use semaphore...
>

I was curious that after a call to preempt_disable(), can I call a
function that MAY sleep?
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Re: Sleeping after preempt_disable() possible?

On Friday 01 September 2006 16:21, Rick Brown wrote:
> > > Can I sleep after a call to preempt_disable() ?
> >
> > What are you trying to do? You can sleep from process context. If two
> > different process context can access to shared data, you can use
> > semaphore...
>
> I was curious that after a call to preempt_disable(), can I call a
> function that MAY sleep?
>

No, you are not allowed to sleep with preemption disabled.


tavi
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Re: Sleeping after preempt_disable() possible?

Rick Brown wrote:

> I was curious that after a call to preempt_disable(), can I call a
> function that MAY sleep?

Bad idea. That can make the kernel do bad things...

Just take a look at schedule() in kernel/sched.c:

asmlinkage void __sched schedule(void)
{
....
if (unlikely(in_atomic() && !current->exit_state)) {
printk(KERN_ERR "BUG: scheduling while atomic: "
"%s/0x%08x/%d\n",
current->comm, preempt_count(), current->pid);
dump_stack();
}

Of course, in_atomic() checks whether you disabled preemption.

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What is important? What you want to be true, or what is true?

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