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-rw-r--r--kernel/trace/ftrace.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a0dc0de8d649..62e26d930535 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -88,6 +88,7 @@ static struct ftrace_ops ftrace_list_end __read_mostly = {
static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
+static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
static struct ftrace_ops global_ops;
@@ -146,9 +147,11 @@ void clear_ftrace_function(void)
{
ftrace_trace_function = ftrace_stub;
__ftrace_trace_function = ftrace_stub;
+ __ftrace_trace_function_delay = ftrace_stub;
ftrace_pid_function = ftrace_stub;
}
+#undef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
/*
* For those archs that do not test ftrace_trace_stop in their
@@ -208,7 +211,12 @@ static void update_ftrace_function(void)
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
+#ifdef CONFIG_DYNAMIC_FTRACE
+ /* do not update till all functions have been modified */
+ __ftrace_trace_function_delay = func;
+#else
__ftrace_trace_function = func;
+#endif
ftrace_trace_function = ftrace_test_stop_func;
#endif
}
@@ -1607,6 +1615,12 @@ static int __ftrace_modify_code(void *data)
{
int *command = data;
+ /*
+ * Do not call function tracer while we update the code.
+ * We are in stop machine, no worrying about races.
+ */
+ function_trace_stop++;
+
if (*command & FTRACE_ENABLE_CALLS)
ftrace_replace_code(1);
else if (*command & FTRACE_DISABLE_CALLS)
@@ -1620,6 +1634,18 @@ static int __ftrace_modify_code(void *data)
else if (*command & FTRACE_STOP_FUNC_RET)
ftrace_disable_ftrace_graph_caller();
+#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
+ /*
+ * For archs that call ftrace_test_stop_func(), we must
+ * wait till after we update all the function callers
+ * before we update the callback. This keeps different
+ * ops that record different functions from corrupting
+ * each other.
+ */
+ __ftrace_trace_function = __ftrace_trace_function_delay;
+#endif
+ function_trace_stop--;
+
return 0;
}