[for-next][PATCH 4/5] tracing: Add warning if string in __assign_str() does not match __string()

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>

In preparation to remove the second parameter of __assign_str(), make sure
it is really a duplicate of __string() by adding a WARN_ON_ONCE().

Link: https://lore.kernel.org/linux-trace-kernel/20240223161356.63b72403@xxxxxxxxxxxxxxxxxx

Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
 include/trace/stages/stage6_event_callback.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index 0c0f50bcdc56..935608971899 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -35,6 +35,7 @@
 	do {								\
 		char *__str__ = __get_str(dst);				\
 		int __len__ = __get_dynamic_array_len(dst) - 1;		\
+		WARN_ON_ONCE((src) != __data_offsets.dst##_ptr_);	\
 		memcpy(__str__, __data_offsets.dst##_ptr_ ? :		\
 		       EVENT_NULL_STR, __len__);			\
 		__str__[__len__] = '\0';				\
-- 
2.43.0