lkml.org 
[lkml]   [2017]   [Apr]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 7/5] tracing: Make sure rcu_irq_enter() can work for trace_*_rcuidle() trace events
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

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 <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
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
\
 
 \ /
  Last update: 2017-04-07 19:07    [W:0.481 / U:0.476 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site