Re: [RFC PATCH] kmemleak: Scan all thread stacks

Catalin Marinas
2009-07-17T16:57:27Z

On Fri, 2009-07-17 at 18:43 +0200, Ingo Molnar wrote:
> * Catalin Marinas <catalin.marinas@arm.com> wrote:
> > 2. Is it safe to use rcu_read_lock() and task_lock() when scanning the
> > corresponding kernel stack (thread_info structure)? The loop doesn't
> > do any modification to the task list. The reason for this is to
> > allow kernel preemption when scanning the stacks.
>
> you cannot generally preempt while holding the RCU read-lock.

This may work with rcupreempt enabled. But, with classic RCU is it safe
to call schedule (or cond_resched) while holding the RCU read-lock?

Thanks.

--
Catalin