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authorSteven Rostedt <srostedt@redhat.com>2011-01-14 19:25:58 +0300
committerSteven Rostedt <rostedt@goodmis.org>2011-01-14 19:25:58 +0300
commitc94fbe1d9e1e9b1a1f82eb0b53b1cf53bcf9712b (patch)
tree0191c752be8ea739136106f6cca95df61cffc676 /include/trace
parent4ad9f594d7199c99f6b1b3ef88c64bd5920a4592 (diff)
downloadlinux-c94fbe1d9e1e9b1a1f82eb0b53b1cf53bcf9712b.tar.xz
tracing: Only process module tracepoints once
The commit: 9f987b3141f086de27832514aad9f50a53f754 tracing: Include module.h in define_trace.h only solved half the problem. If the trace/events/module.h header is included at the time of define_trace.h (or in ftrace.h within it), the module.h TRACE_SYSTEM will override the current TRACE_SYSTEM macro. Since define_trace.h is included when CREATE_TRACE_POINTS is set, and the first thing it does is to #undef CREATE_TRACE_POINTS, by placing the module.h TRACE_SYSTEM inside a #ifdef CREATE_TRACE_POINTS we can prevent it from overriding the TRACE_SYSTEM that is being processed, and still process the module.h tracepoints when the module code defines CREATE_TRACE_POINTS and includes the trace/events/module.h header. As with commit 9f987b3141, this is only an issue if module.h is not included before the trace/events/<event>.h file is included, which (luckily) has not happened yet. Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/module.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index c7bb2f0482fe..c6bae36547e5 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -1,5 +1,15 @@
+/*
+ * Because linux/module.h has tracepoints in the header, and ftrace.h
+ * eventually includes this file, define_trace.h includes linux/module.h
+ * But we do not want the module.h to override the TRACE_SYSTEM macro
+ * variable that define_trace.h is processing, so we only set it
+ * when module events are being processed, which would happen when
+ * CREATE_TRACE_POINTS is defined.
+ */
+#ifdef CREATE_TRACE_POINTS
#undef TRACE_SYSTEM
#define TRACE_SYSTEM module
+#endif
#if !defined(_TRACE_MODULE_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_MODULE_H