Re: [PATCH 6.1.y] tracing: Do not add length to print format in synthetic events

Hi Sasha,

On 07-09-2025 23:25, Sasha Levin wrote:

1 file changed, 2 deletions(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 385e9fbbfbe7c..c2817d0c05b69 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -383,13 +383,11 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter, str_field = (char *)entry + data_offset; trace_seq_printf(s, print_fmt, se->fields[i]->name,

• 				 STR_VAR_LEN_MAX,
  			 str_field,
  			 i == se->n_fields - 1 ? "" : " ");
  	n_u64++;
  } else {
  	trace_seq_printf(s, print_fmt, se->fields[i]->name,
  

• 				 STR_VAR_LEN_MAX,
  			 (char *)&entry->fields[n_u64],
  			 i == se->n_fields - 1 ? "" : " ");
  	n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
  

This looks consistent to me with that patch: [PATCH v2] tracing: Fix synth event printk format for str fields

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index e3f7d09e5512..f71e49cd35b0 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -305,7 +305,7 @@ static const char *synth_field_fmt(char *type) else if (strcmp(type, "gfp_t") == 0) fmt = "%x"; else if (synth_field_is_string(type)) - fmt = "%.*s"; + fmt = "%s"; else if (synth_field_is_stack(type)) fmt = "%s";

I only tested the trace.dat route when writing it, thanks for catching this case.

Cheers,

Douglas