Re: [PATCH -tip] rcu: local_irq_disable() also delimits RCU_SCHEDread-site critical sections

From: Ingo Molnar
Date: Tue Mar 16 2010 - 07:28:37 EST



* Lai Jiangshan <laijs@xxxxxxxxxxxxxx> wrote:

> It is documented that local_irq_disable() also delimits
> RCU_SCHED read-site critical sections.
> See the document of synchronize_sched() or
> Documentation/RCU/whatisRCU.txt.
>
> So we have to test irqs_disabled() in rcu_read_lock_sched_held().
> Otherwise rcu-lockdep brings incorrect complaint.

It would be useful to include the warning in question in the changelog - so
that others who might be affected by it can see the fix and can track its
progress. (and dont start a parallel effort debugging/reporting/fixing it)

Thanks,

Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/