[RFC PATCH v2] compat: poll() in 32-bit applications does not handle negative timeout values properly on 64-bit kernels

We have hit an issue where our 32-bit applications using poll() and
passing in a value of -1 for the timeout value return after ~49 days
(2^32 msec), instead of waiting indefinitely. I've instrumented the
kernel and found we are hitting the case where poll() believes we've
passed in a positive number and thus creates a timespec, etc. I've
implemented compat_sys_poll() to sign-extend the timeout value and
resolve the issue.

There was an almost identical patch submitted last year, but for
whatever reason did not make it in:
https://lkml.org/lkml/2011/9/18/19

I am guessing there are other architectures affected by this bug. This
patch only fixes x86.

Josh