[PATCH 01/13] jump label v8: notifier atomic call chain notrace

From: Jason Baron
Date: Wed May 19 2010 - 12:22:24 EST

From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>

In LTTng, being able to use the atomic notifier from cpu idle entry to
ensure the tracer flush the last events in the current subbuffer
requires the rcu read-side to be marked "notrace", otherwise it can end
up calling back into lockdep and the tracer.

Also apply to the the die notifier.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
kernel/notifier.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/notifier.c b/kernel/notifier.c
index 2488ba7..88453a7 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -148,7 +148,7 @@ int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
spin_lock_irqsave(&nh->lock, flags);
ret = notifier_chain_unregister(&nh->head, n);
spin_unlock_irqrestore(&nh->lock, flags);
- synchronize_rcu();
+ synchronize_sched();
return ret;
@@ -178,9 +178,9 @@ int __kprobes __atomic_notifier_call_chain(struct atomic_notifier_head *nh,
int ret;

- rcu_read_lock();
+ rcu_read_lock_sched_notrace();
ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
- rcu_read_unlock();
+ rcu_read_unlock_sched_notrace();
return ret;

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