Re: 2.6.12-rc2 in_atomic() picks up preempt_disable()

From: Ingo Molnar
Date: Thu Apr 07 2005 - 09:57:59 EST



* Keith Owens <kaos@xxxxxxx> wrote:

> 2.6.12-rc2, with CONFIG_PREEMPT and CONFIG_PREEMPT_DEBUG. The
> in_atomic() macro thinks that preempt_disable() indicates an atomic
> region so calls to __might_sleep() result in a stack trace.
> preempt_count() returns 1, no soft or hard irqs are running and no
> spinlocks are held. It looks like there is no way to distinguish
> between the use of preempt_disable() in the lock functions (atomic)
> and preempt_disable() outside the lock functions (do nothing that
> might migrate me).

preempt_disable() sections are just as much atomic as spinlocked
regions. Like the name suggests it.

Ingo
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