trace: Allow idle-safe tracepoints to be called from irq
__DECLARE_TRACE_RCU() currently creates an _rcuidle() tracepoint which
may safely be invoked from what RCU considers to be an idle CPU.
However, these _rcuidle() tracepoints may -not- be invoked from the
handler of an irq taken from idle, because rcu_idle_enter() zeroes
RCU's nesting-level counter, so that the rcu_irq_exit() returning to
idle will trigger a WARN_ON_ONCE().
This commit therefore substitutes rcu_irq_enter() for rcu_idle_exit()
and rcu_irq_exit() for rcu_idle_enter() in order to make the _rcuidle()
tracepoints usable from irq handlers as well as from process context.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 2f322c3..f8e084d 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -145,8 +145,8 @@
TP_PROTO(data_proto), \
TP_ARGS(data_args), \
TP_CONDITION(cond), \
- rcu_idle_exit(), \
- rcu_idle_enter()); \
+ rcu_irq_enter(), \
+ rcu_irq_exit()); \
}
#else
#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)