Re: [PATCH 5/8] membarrier, kthread: Use _ONCE accessors for task->mm

[Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>]

----- On Jun 15, 2021, at 11:21 PM, Andy Lutomirski luto@xxxxxxxxxx wrote:

> membarrier reads cpu_rq(remote cpu)->curr->mm without locking.  Use
> READ_ONCE() and WRITE_ONCE() to remove the data races.

I notice that kernel/exit.c:exit_mm() also has:

        current->mm = NULL;

I suspect you may want to add a WRITE_ONCE() there as well ?

Thanks,

Mathieu


-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com