tree da761ad8810ea53199d87602d900652d529c8adb
parent 39953dfd40077c7480b1d5deb4d617e086b1c865
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1407868051 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1410887283 -0700

rcu: Handle NOCB callbacks from irq-disabled idle code

If an RCU callback is queued on a no-CBs CPU from idle code with irqs
disabled, and if that CPU stays idle forever after, the callback will
never be invoked.  This commit therefore adds a check for this situation
in ____call_rcu_nocb(), invoking the RCU core solely for the purpose
of the ensuing return-to-idle transition.  (If the CPU doesn't return
to idle, the next scheduling-clock interrupt will fix things up.)

Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>