Re: [BUG] completely bonkers use of set_need_resched + VM_FAULT_NOPAGE

[Thomas Hellstrom]

On 09/13/2013 10:32 AM, Daniel Vetter wrote:
> On Fri, Sep 13, 2013 at 10:23 AM, Thomas Hellstrom
> <thellstrom@xxxxxxxxxx> wrote:
> > As previously mentioned, copy_from_user should return -EFAULT, since the
> > VMAs are marked with VM_IO. It should not recurse into fault(), so evil
> > user-space looses.
> I haven't put a printk in the code to prove this, but gem mmap also
> sets VM_IO in drm_gem_mmap_obj. And we can very much hit our own fault
> handler and deadlock ....

If this is indeed true, I guess I need to accept the fact that my 
solution is bad.
(and worse I can't blame not having my morning coffee).

I'll take a deeper look.
/Thomas
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