rcu: Make RCU lockdep check the lockdep_recursion variable

The lockdep facility temporarily disables lockdep checking by
incrementing the current->lockdep_recursion variable.  Such
disabling happens in NMIs and in other situations where lockdep
might expect to recurse on itself.

This patch therefore checks current->lockdep_recursion, disabling RCU
lockdep splats when this variable is non-zero.  In addition, this patch
removes the "likely()", as suggested by Lai Jiangshan.

Reported-by: Frederic Weisbecker <[email protected]>
Reported-by: David Miller <[email protected]>
Tested-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Paul E. McKenney 2010-04-15 12:50:39 -07:00 • committed by Ingo Molnar
commit bc293d62b2
2 changed files with 8 additions and 4 deletions

View file

@ -69,6 +69,13 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
int debug_lockdep_rcu_enabled(void)
{
return rcu_scheduler_active && debug_locks &&
current->lockdep_recursion == 0;
}
EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
/**
* rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section?
*