From: Ulrich Drepper <redacted>
Date: Sat, 31 Mar 2012 08:30:25 -0400

On Fri, Mar 30, 2012 at 20:51, David Miller [off-list ref] wrote:

quoted

Compat processes are not able to generate virtual addresses anywhere
near the range where the kernel resides, so the address range
verification done by put_user() is completely superfluous and
therefore not necessary.  The normal exception handling done by the
access is completely sufficient.

I was more thinking about the effects of might_fault() then additional tests.

This is very clearly in a context where locks are not held and sleeping
would be fine, so I don't see any value in that either.