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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-04-15 12:50:39 -0700
committerIngo Molnar <mingo@elte.hu>2010-04-19 08:37:19 +0200
commitbc293d62b26ec590afc90a9e0a31c45d355b7bd8 (patch)
tree4b61dee53e849f0ba1d5a7fef58522e224be836e /kernel/rcupdate.c
parent50aec0024eccb1d5f540ab64a1958eebcdb9340c (diff)
downloadlinux-linaro-stable-bc293d62b26ec590afc90a9e0a31c45d355b7bd8.tar.gz
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 <fweisbec@gmail.com> Reported-by: David Miller <davem@davemloft.net> Tested-by: Frederic Weisbecker <fweisbec@gmail.com> 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 Cc: eric.dumazet@gmail.com LKML-Reference: <20100415195039.GA22623@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcupdate.c')
-rw-r--r--kernel/rcupdate.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 63fe25433980..03a7ea1579f6 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -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?
*