Re: [Fwd: [-mm] Add an owner to the mm_struct (v9)]

From: Oleg Nesterov
Date: Thu Apr 17 2008 - 14:03:59 EST


On 04/17, Balbir Singh wrote:
>
> Oleg Nesterov wrote:
> >> CLONE_THREAD without CLONE_VM when creating a new subthread.
> >
> > No, no, this is not possible/allowed.
> >
> > Please look at copy_process, CLONE_THREAD requires CLONE_SIGHAND,
> > CLONE_SIGHAND needs CLONE_VM.
> >
>
> What about the other way round, CLONE_VM without CLONE_THREAD?

Yes, this is possible, and this is why mm_update_next_owner() has to be so
complicated. The same for zap_threads/elf_core_dump.

If only I knew why we allow CLONE_VM! except for CLONE_THREAD/CLONE_VFORK
of course, but there are trivial.


And thanks to you and Paul for your explanations.

Oleg.

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