From: "Steven Rostedt (Google)" <[email protected]>
When CONFIG_DYNAMIC_FTRACE is not set, the function
fgraph_update_pid_func() doesn't do anything. Currently, most of its logic
is within a "#ifdef CONFIG_DYNAMIC_FTRACE" block, but its variables were
declared outside that, and when DYNAMIC_FTRACE is not set, it produces
unused variable warnings.
Instead, just place it (and the helper function fgraph_pid_func()) within
the #ifdef block and have the header file use a empty stub function for
when DYNAMIC_FTRACE is not defined.
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Signed-off-by: Steven Rostedt (Google) <[email protected]>
---
kernel/trace/fgraph.c | 4 ++--
kernel/trace/ftrace_internal.h | 4 ++++
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index c0e428c87ea5..0859ab112db7 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -1151,6 +1151,7 @@ void ftrace_graph_exit_task(struct task_struct *t)
kfree(ret_stack);
}
+#ifdef CONFIG_DYNAMIC_FTRACE
static int fgraph_pid_func(struct ftrace_graph_ent *trace,
struct fgraph_ops *gops)
{
@@ -1177,7 +1178,6 @@ void fgraph_update_pid_func(void)
if (!(graph_ops.flags & FTRACE_OPS_FL_INITIALIZED))
return;
-#ifdef CONFIG_DYNAMIC_FTRACE
list_for_each_entry(op, &graph_ops.subop_list, list) {
if (op->flags & FTRACE_OPS_FL_PID) {
gops = container_of(op, struct fgraph_ops, ops);
@@ -1187,8 +1187,8 @@ void fgraph_update_pid_func(void)
static_call_update(fgraph_func, gops->entryfunc);
}
}
-#endif
}
+#endif
/* Allocate a return stack for each task */
static int start_graph_tracing(void)
diff --git a/kernel/trace/ftrace_internal.h b/kernel/trace/ftrace_internal.h
index 4bb1e881154a..3235470e61b3 100644
--- a/kernel/trace/ftrace_internal.h
+++ b/kernel/trace/ftrace_internal.h
@@ -52,7 +52,11 @@ static inline int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_o
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
extern int ftrace_graph_active;
+# ifdef CONFIG_DYNAMIC_FTRACE
extern void fgraph_update_pid_func(void);
+# else
+static inline void fgraph_update_pid_func(void) {}
+# endif
#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
# define ftrace_graph_active 0
static inline void fgraph_update_pid_func(void) {}
--
2.43.0