rcu: Improve diagnostics for blocked critical sections in irq

Browse source

If an RCU read-side critical section occurs within an interrupt handler
or a softirq handler, it cannot have been preempted.  Therefore, there is
a check in rcu_read_unlock_special() checking for this error.  However,
when this check triggers, it lacks diagnostic information.  This commit
therefore moves rcu_read_unlock()'s lockdep annotation to follow the
call to __rcu_read_unlock() and changes rcu_read_unlock_special()'s
WARN_ON_ONCE() to an lockdep_rcu_suspicious() in order to locate where
the offending RCU read-side critical section began.  In addition, the
value of the ->rcu_read_unlock_special field is printed.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

...

This commit is contained in:

Paul E. McKenney 2015-01-21 15:26:03 -08:00

parent 6629240575

commit d24209bb68

3 changed files with 14 additions and 3 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

7

include/linux/lockdep.h

View file

2

include/linux/rcupdate.h

View file

8

kernel/rcu/tree_plugin.h

View file