Re: [PATCH] Tracepoints synchronize unregister static inline

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

* Ingo Molnar (mingo@elte.hu) wrote:
> 
> * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote:
> 
> > Ingo, could you pull the following patch into -tip ?
> 
> sure - but it does not apply to tip/master. Some missing dependencies?
> 
> 	Ingo

Hi Ingo,

"Tracepoints synchronize unregister static inline"
applies on top of
"Tracepoints : tracepoint_synchronize_unregister()"

I posted earlier but does not seem to be in tip/master. Here is a repost
:

Tracepoints : tracepoint_synchronize_unregister()

Create tracepoint_synchronize_unregister() which must be called before the end
of exit() to make sure every probe callers have exited the non preemptible
section and thus are not executing the probe code anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: "Frank Ch. Eigler" <fche@redhat.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/tracepoint.h |    7 +++++++
 1 file changed, 7 insertions(+)

Index: linux-2.6-lttng/include/linux/tracepoint.h
===================================================================
--- linux-2.6-lttng.orig/include/linux/tracepoint.h	2008-07-31 09:21:40.000000000 -0400
+++ linux-2.6-lttng/include/linux/tracepoint.h	2008-07-31 09:22:27.000000000 -0400
@@ -124,4 +124,11 @@ extern void tracepoint_iter_reset(struct
 extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
 	struct tracepoint *begin, struct tracepoint *end);
 
+/*
+ * tracepoint_synchronize_unregister must be called between the last tracepoint
+ * probe unregistration and the end of module exit to make sure there is no
+ * caller executing a probe when it is freed.
+ */
+#define tracepoint_synchronize_unregister() synchronize_sched()
+
 #endif

-- 
Mathieu Desnoyers
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