tracing: Add stack_tracer_disable/enable() functions

There are certain parts of the kernel that cannot let stack tracing
proceed (namely in RCU), because the stack tracer uses RCU, and parts of RCU
internals cannot handle having RCU read side locks taken.

Add stack_tracer_disable() and stack_tracer_enable() functions to let RCU
stop stack tracing on the current CPU when it is in those critical sections.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index ef7123219f14..7b4e6572ab21 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -286,6 +286,12 @@ int
 stack_trace_sysctl(struct ctl_table *table, int write,
                    void __user *buffer, size_t *lenp,
                    loff_t *ppos);
+
+void stack_tracer_disable(void);
+void stack_tracer_enable(void);
+#else
+static inline void stack_tracer_disable(void) { }
+static inline void stack_tracer_enable(void) { }
 #endif
 
 struct ftrace_func_command {