[for-next][PATCH 10/10] tracing: Fix synth event printk format for str fields

[Steven Rostedt <rostedt@goodmis.org>]

From: Douglas Raillard <douglas.raillard@arm.com>

The printk format for synth event uses "%.*s" to print string fields,
but then only passes the pointer part as var arg.

Add the missing precision var arg.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250318180939.227696-1-douglas.raillard@arm.com
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_synth.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 463b0073629a..d91205bc9f61 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -620,7 +620,8 @@ static int __set_synth_event_print_fmt(struct synth_event *event,
 		if (event->fields[i]->is_string &&
 		    event->fields[i]->is_dynamic)
 			pos += snprintf(buf + pos, LEN_OR_ZERO,
-				", __get_str(%s)", event->fields[i]->name);
+				", (int)__get_dynamic_array_len(%s), __get_str(%s)",
+				event->fields[i]->name, event->fields[i]->name);
 		else if (event->fields[i]->is_stack)
 			pos += snprintf(buf + pos, LEN_OR_ZERO,
 				", __get_stacktrace(%s)", event->fields[i]->name);
-- 
2.47.2