rcu: Check for timer migration for RCU_FAST_NO_HZ
If RCU_FAST_NO_HZ's timer is migrated, then the CPU that went dyntick-idle
with callbacks might never wake up, which could indefinitely postpone
invocation of its callbacks, which could in turn result in a system hang.
But if the timer is migrated, then it might actually fire. In contrast,
if it remains on the CPU that posted it, it is guaranteed to be cancelled.
This patch therefore adds a WARN_ON_ONCE() to this timer's handler as
a diagnostic test.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
1 file changed
