From 33974093c024f08caadd2fc71a83bd811ed1831d Mon Sep 17 00:00:00 2001
From: Matt Fleming <matthew.fleming@imgtec.com>
Date: Mon, 28 Sep 2009 16:43:01 +0100
Subject: [PATCH] tracing: Fix infinite recursion in ftrace_update_pid_func()
When CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST is enabled
__ftrace_trace_function contains the current trace function, not
ftrace_trace_function.
In ftrace_update_pid_func() we currently incorrectly assign the
value of ftrace_trace_function to __ftrace_trace_funcion before
returning.
Without this patch it is possible to execute an infinite recursion
whereby ftrace_test_stop_func() calls __ftrace_trace_function,
which was assigned ftrace_test_stop_func() in
ftrace_update_pid_func().
Signed-off-by: Matt Fleming <matthew.fleming@imgtec.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1254152581-18347-1-git-send-email-matt@console-pimps.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/trace/ftrace.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 46592feab5a6b..3724756e41ca9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -225,7 +225,11 @@ static void ftrace_update_pid_func(void)
if (ftrace_trace_function == ftrace_stub)
return;
+#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
func = ftrace_trace_function;
+#else
+ func = __ftrace_trace_function;
+#endif
if (ftrace_pid_trace) {
set_ftrace_pid_function(func);
--
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