diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-01-04 16:04:01 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-01-13 09:06:06 +0100 |
| commit | cba8244a0f1c277b6b1e48ed6504fa434119e24d (patch) | |
| tree | becfa7d6f653774f72f411002626e791243e5057 /kernel/rcutree_plugin.h | |
| parent | f9094d8e5587cf21091a9516628147c0b55e4264 (diff) | |
| download | lwn-cba8244a0f1c277b6b1e48ed6504fa434119e24d.tar.gz lwn-cba8244a0f1c277b6b1e48ed6504fa434119e24d.zip | |
rcu: Add debug check for too many rcu_read_unlock()
TREE_PREEMPT_RCU maintains an rcu_read_lock_nesting counter in
the task structure, which happens to be a signed int. So this
patch adds a check for this counter being negative at the end of
__rcu_read_unlock(). This check is under CONFIG_PROVE_LOCKING,
so can be thought of as being part of lockdep.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12626498423064-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcutree_plugin.h')
| -rw-r--r-- | kernel/rcutree_plugin.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index f11ebd44b454..e77cdf321e13 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -304,6 +304,9 @@ void __rcu_read_unlock(void) if (--ACCESS_ONCE(t->rcu_read_lock_nesting) == 0 && unlikely(ACCESS_ONCE(t->rcu_read_unlock_special))) rcu_read_unlock_special(t); +#ifdef CONFIG_PROVE_LOCKING + WARN_ON_ONCE(ACCESS_ONCE(t->rcu_read_lock_nesting) < 0); +#endif /* #ifdef CONFIG_PROVE_LOCKING */ } EXPORT_SYMBOL_GPL(__rcu_read_unlock); |