From: "Steven Rostedt (VMware)" <[email protected]> Stack tracing discovered that there's a small location inside the RCU infrastructure that calling rcu_irq_enter() does not work. As trace events use rcu_irq_enter() it must make sure that it is functionable. A check against rcu_irq_enter_disabled() is added with a WARN_ON_ONCE() as no trace event should ever be used in that part of RCU. If the warning is triggered, then the trace event is ignored.
Cc: Mathieu Desnoyers <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]> --- include/linux/tracepoint.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index f72fcfe..8baef96 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -159,6 +159,8 @@ extern void syscall_unregfunc(void); TP_PROTO(data_proto), \ TP_ARGS(data_args), \ TP_CONDITION(cond), \ + if (WARN_ON_ONCE(rcu_irq_enter_disabled())) \ + return; \ rcu_irq_enter_irqson(), \ rcu_irq_exit_irqson()); \ } -- 2.9.3
