On 06/30, Michal Hocko wrote:

On Wed 29-06-16 22:14:09, Oleg Nesterov wrote:

quoted

On 06/28, Michal Hocko wrote:

quoted

Could you point me to where it depends on that? I mean if we are past
exit_mm then we have unmapped the address space most probably but why
should we care about that in the scheduler? There shouldn't be any
further access to the address space by that point. I can see that
context_switch() checks task->mm but it should just work when it sees it
non NULL, right?

But who will do the final mmdrop() then? I am not saying this is impossible
to change, say we do this in finish_task_switch(TASK_DEAD) or even in
free_task(), but we do not want this?

I thought it could be done somewhere in release_task after we unhash
the process

No, we can't do this. Note that release_task() can be called right after
exit_notify() by its parent ot by the exiting thread itself. It can still
run after that and it needs ->active_mm.

Oleg.

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