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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: [RFC][PATCH 1/5] tracing: Make sure RCU is watching before calling a stack trace
Date: Fri, 12 May 2017 13:15:45 -0400
Message-ID: <20170512172449.879684501@goodmis.org> (raw)
In-Reply-To: <20170512171544.100715273@goodmis.org>


[-- Attachment #0: 0001-tracing-Make-sure-RCU-is-watching-before-calling-a-s.patch --]
[-- Type: text/plain, Size: 801 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

As stack tracing now requires "rcu watching", force RCU to be watching when
recording a stack trace.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c4536c449021..a4208cebb42b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2568,7 +2568,12 @@ static inline void ftrace_trace_stack(struct trace_array *tr,
 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
 		   int pc)
 {
+	if (unlikely(rcu_irq_enter_disabled()))
+		return;
+
+	rcu_irq_enter();
 	__ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
+	rcu_irq_exit();
 }
 
 /**
-- 
2.10.2

  reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-12 17:15 [RFC][PATCH 0/5] perf/tracing/cpuhotplug: Fix locking order Steven Rostedt
2017-05-12 17:15 ` Steven Rostedt [this message]
2017-05-12 18:25   ` [RFC][PATCH 1/5] tracing: Make sure RCU is watching before calling a stack trace Paul E. McKenney
2017-05-12 18:36     ` Steven Rostedt
2017-05-12 18:50       ` Paul E. McKenney
2017-05-12 20:05         ` Steven Rostedt
2017-05-12 20:31           ` Paul E. McKenney
2017-05-17 16:46             ` Steven Rostedt
2017-05-12 17:15 ` [RFC][PATCH 2/5] cpu-hotplug: Allow get_online_cpus() to nest Steven Rostedt
2017-05-12 18:35   ` Paul E. McKenney
2017-05-12 18:40     ` Steven Rostedt
2017-05-12 18:52       ` Paul E. McKenney
2017-05-12 22:15   ` Thomas Gleixner
2017-05-13  0:23     ` Steven Rostedt
2017-05-12 17:15 ` [RFC][PATCH 3/5] kprobes: Take get_online_cpus() before taking jump_label_lock() Steven Rostedt
2017-05-12 18:39   ` Paul E. McKenney
2017-05-12 18:44     ` Steven Rostedt
2017-05-17 17:50   ` Masami Hiramatsu
2017-05-12 17:15 ` [RFC][PATCH 4/5] tracepoints: Grab get_online_cpus() before taking tracepoints_mutex Steven Rostedt
2017-05-12 17:15 ` [RFC][PATCH 5/5] perf: Grab event_mutex before taking get_online_cpus() Steven Rostedt
2017-05-12 18:13 ` [RFC][PATCH 0/5] perf/tracing/cpuhotplug: Fix locking order Paul E. McKenney
2017-05-12 19:49 ` Peter Zijlstra
2017-05-12 20:14   ` Steven Rostedt
2017-05-12 21:34   ` Steven Rostedt
2017-05-13 13:40     ` Paul E. McKenney
2017-05-15  9:03       ` Peter Zijlstra
2017-05-15 18:40         ` Paul E. McKenney
2017-05-16  8:19           ` Peter Zijlstra
2017-05-16 12:46             ` Paul E. McKenney
2017-05-16 14:27               ` Paul E. McKenney
2017-05-17 10:40                 ` Peter Zijlstra
2017-05-17 14:55                   ` Paul E. McKenney
2017-05-18  3:58                     ` Paul E. McKenney
2017-05-15 19:06   ` Steven Rostedt

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