rcu: Add lockdep-RCU checks for simple self-deadlock

It is illegal to have a grace period within a same-flavor RCU read-side
critical section, so this commit adds lockdep-RCU checks to splat when
such abuse is encountered.  This commit does not detect more elaborate
RCU deadlock situations.  These situations might be a job for lockdep
enhancements.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2012-01-04 13:30:33 -08:00
parent 18fec7d875
commit fe15d706cf
5 changed files with 27 additions and 0 deletions

View file

@ -319,6 +319,10 @@ static void rcu_process_callbacks(struct softirq_action *unused)
*/
void synchronize_sched(void)
{
rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
!lock_is_held(&rcu_lock_map) &&
!lock_is_held(&rcu_sched_lock_map),
"Illegal synchronize_sched() in RCU read-side critical section");
cond_resched();
}
EXPORT_SYMBOL_GPL(synchronize_sched);