linux/kernel/rcu
Paul E. McKenney 19a5ecde08 rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex
In kernels built with CONFIG_PREEMPT=y, synchronize_rcu_expedited()
invokes synchronize_sched_expedited() while holding RCU-preempt's
root rcu_node structure's ->exp_funnel_mutex, which is acquired after
the rcu_data structure's ->exp_funnel_mutex.  The first thing that
synchronize_sched_expedited() will do is acquire RCU-sched's rcu_data
structure's ->exp_funnel_mutex.   There is no danger of an actual deadlock
because the locking order is always from RCU-preempt's expedited mutexes
to those of RCU-sched.  Unfortunately, lockdep considers both rcu_data
structures' ->exp_funnel_mutex to be in the same lock class and therefore
reports a deadlock cycle.

This commit silences this false positive by placing RCU-sched's rcu_data
structures' ->exp_funnel_mutex locks into their own lock class.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-09-20 21:01:22 -07:00
..
Makefile rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
rcu.h tiny_rcu: Directly force QS when call_rcu_[bh|sched]() on idle_task 2015-01-06 11:01:12 -08:00
rcutorture.c Merge branches 'doc.2015.07.15a' and 'torture.2015.07.15a' into HEAD 2015-08-04 08:42:02 -07:00
srcu.c rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN() 2015-07-22 15:27:32 -07:00
tiny.c rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN() 2015-07-22 15:27:32 -07:00
tiny_plugin.h rcu: Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE() 2015-05-27 12:56:15 -07:00
tree.c rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex 2015-09-20 21:01:22 -07:00
tree.h rcu,locking: Privatize smp_mb__after_unlock_lock() 2015-08-04 08:49:21 -07:00
tree_plugin.h Merge branches 'fixes.2015.07.22a' and 'initexp.2015.08.04a' into HEAD 2015-08-04 08:40:58 -07:00
tree_trace.c rcu: Add fastpath bypassing funnel locking 2015-07-17 14:59:06 -07:00
update.c rcu: Fix backwards RCU_LOCKDEP_WARN() in synchronize_rcu_tasks() 2015-07-22 15:27:33 -07:00