Re: [patch] fixed both processes in D state and the /proc/ oopses [Re: [patch] Fixed the race that w

Linus Torvalds (torvalds@transmeta.com)
Thu, 28 Jan 1999 16:17:42 -0800 (PST)

On Thu, 28 Jan 1999, Andrea Arcangeli wrote:
>
> If you remove the kernel lock around do_exit() you _need_ my mm_lock
> spinlock. You need it to make atomic the decreasing of mm->count and
> current->mm = &init_mm. If the two instructions are not atomic you have
> _no_ way to know if you can mmget() at any time the mm of a process.

Andrea, just go away.

The two do not _have_ to be atomic, they never had to, and they never
_will_ have to be atomic. You obviously haven't read all my email
explaining why they don't have to be atomic.

> I repeat in another way (just trying to avoid English mistakes):
> decreasing mm->count has to go in sync with updating current->mm,

No it has not.

Linus

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