Re: [PATCH v4] mm: per-thread vma caching

From: Linus Torvalds
Date: Sun Mar 09 2014 - 13:16:41 EST


On Sun, Mar 9, 2014 at 10:09 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>
> But it's not the "while we're setting up a new thread", it is "since
> vmacache_valid() was called list time". And the cloning task can just
> sleep(A_LOT) and then do CLONE_VM.
>
> Of course, of course, this race is pute theoretical anyway. But imho
> makes sense to fix anyway, and the natural/trivial approach is just to
> move vmacache_flush(tsk) from dup_mm() to copy_mm(), right after the
> "if (!oldmm)" check.

Fair enough, you've convinced me it's subtle enough that we do not
want to play games..

Linus
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