Re: [RFC PATCH] percpu system call: fast userspace percpu critical sections

[Linus Torvalds]

On Thu, May 21, 2015 at 7:44 AM, Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
> Expose a new system call allowing userspace threads to register
> a TLS area used as an ABI between the kernel and userspace to
> share information required to create efficient per-cpu critical
> sections in user-space.

Not a way in hell.

You do user accesses from preempt notifiers.

That's so ludicrously broken that it's not even funny.

This patch needs to die, and never *ever* be resurrected. Put a stake
in it, and bury it 6ft deep.

               Linus
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