Re: [PATCH 2.6.16-rc1-git4] accessfs: a permission managingfilesystem

From: Arjan van de Ven
Date: Mon Jan 30 2006 - 05:37:30 EST


On Mon, 2006-01-30 at 11:36 +0100, Jan Engelhardt wrote:
> >
> >well... maybe.
> >If you need to mess inside irq context, spinlocks sound more the right
> >thing. Or if you need to do a "I'm done" in the irq and a "sleep until
> >done" thing in process context, then you really should use completions
> >instead.
>
> Hm, is it allowed to call copy_{from,to}_user() in irq context?

absolutely not.

IRQ context has no defined "userspace" context at all, so even if
copy_from/to_user wouldn't sleep (they do, and that alone makes it
"illegal" to do already) it would be highly undefined what you would be
copying to/from.



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