Re: [PATCH 1/2] kthread: add a missing memory barrier to kthread_stop()

From: Rusty Russell
Date: Sun Mar 02 2008 - 16:51:37 EST


On Thursday 21 February 2008 08:36:30 Dmitry Adamushko wrote:
> From: Dmitry Adamushko <dmitry.adamushko@xxxxxxxxx>
> Subject: kthread: add a missing memory barrier to kthread_stop()
>
> We must ensure that kthread_stop_info.k has been updated before
> kthread's wakeup. This is required to properly support
> the use of kthread_should_stop() in the main loop of kthread.
>
> wake_up_process() doesn't imply a full memory barrier,
> so we add an explicit one.

I always believed that wake_up_process() implies a write barrier. It's pretty
common to set something up then wake the intended recipient.

So I think this patch is overkill, but I'm happy to be corrected.

Thanks!
Rusty.
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