Drop CPU_DTRACE_NOFAULT manipulation around ustack calls.
dtrace_getufpstack() and (as of the last commit) dtrace_getustackdepth() both
manipulate the CPU_DTRACE_NOFAULT flag themselves: clearing it after calling
those functions is redundant, and setting it is actually dangerous, since
other functions dtrace_getustackdepth() calls (such as __get_user_pages() do
not expect to have instructions that incur page faults silently skipped without
faulting.
Orabug:
18412802
Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>
Acked-by: Chuck Anderson <chuck.anderson@oracle.com>