Re: [RFC PATCH 4/4] Fix: sched/membarrier: p->mm->membarrier_state racy load (v2)

From: Mathieu Desnoyers
Date: Fri Sep 13 2019 - 13:07:06 EST

----- On Sep 13, 2019, at 12:04 PM, Oleg Nesterov oleg@xxxxxxxxxx wrote:

> On 09/13, Mathieu Desnoyers wrote:
>> membarrier_exec_mmap(), which seems to be affected by the same problem.
> IIRC, in the last version it is called by exec_mmap() undef task_lock(),
> so it should fine.

Fair point. Although it seems rather cleaner to use this_cpu_write() in
all 3 sites updating this variable rather than a mix of this_cpu_write
and WRITE_ONCE(), unless anyone objects.



Mathieu Desnoyers
EfficiOS Inc.