[PATCH] synthetic tracing: Fix trace_string() return value

[Thorsten Blum]

Fix trace_string() by assigning the string length to the return variable
which got lost in commit ddeea494a16f ("tracing/synthetic: Use union
instead of casts") and caused trace_string() to always return 0.

Signed-off-by: Thorsten Blum <thorsten.b...@toblux.com>
---
 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 e7af286af4f1..c82b401a294d 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -441,8 +441,9 @@ static unsigned int trace_string(struct synth_trace_event 
*entry,
        if (is_dynamic) {
                union trace_synth_field *data = &entry->fields[*n_u64];
 
+               len = fetch_store_strlen((unsigned long)str_val);
                data->as_dynamic.offset = struct_size(entry, fields, 
event->n_u64) + data_size;
-               data->as_dynamic.len = fetch_store_strlen((unsigned 
long)str_val);
+               data->as_dynamic.len = len;
 
                ret = fetch_store_string((unsigned long)str_val, 
&entry->fields[*n_u64], entry);
 
-- 
2.39.2