tree 07426bae4e4500acc8bc64a0edd0c6fe6b298e6e
parent 22df7316ac71dc1ac57415349938737d2a229c59
author Peter Zijlstra <peterz@infradead.org> 1527007853 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1527030746 -0700

rcu/x86: Provide early rcu_cpu_starting() callback

The x86/mtrr code does horrific things because hardware. It uses
stop_machine_from_inactive_cpu(), which does a wakeup (of the stopper
thread on another CPU), which uses RCU, all before the CPU is onlined.

RCU complains about this, because wakeups use RCU and RCU does
(rightfully) not consider offline CPUs for grace-periods.

Fix this by initializing RCU way early in the MTRR case.

Tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Add !SMP support, per 0day Test Robot report. ]