From 4b9536382c8cbff744df1ba7b17b54efaa4c4dd0 Mon Sep 17 00:00:00 2001
From: Danylo Piliaiev <dpiliaiev@igalia.com>
Date: Fri, 2 Jan 2026 16:51:31 +0100
Subject: [PATCH] util/u_trace: Fix usage of variable-sized strings in
 non-queued case

When tracepoint is not queued, the memory for it is allocated on stack
and no memory is allocated for variable-sized strings. So we shouldn't
copy or print them in non-queued case.

Signed-off-by: Danylo Piliaiev <dpiliaiev@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/39128>
---
 src/util/perf/u_trace.py | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/util/perf/u_trace.py b/src/util/perf/u_trace.py
index f1640b66af4..4fb8d3cb43e 100644
--- a/src/util/perf/u_trace.py
+++ b/src/util/perf/u_trace.py
@@ -513,13 +513,13 @@ __attribute__((format(printf, 3, 4))) void ${trace.tp_markers}(struct u_trace_co
 static void __emit_label_${trace_name}(struct u_trace_context *utctx, void *cs, struct trace_${trace_name} *entry) {
    ${trace.tp_markers}(utctx, cs, "${trace_name}("
    % for idx,arg in enumerate(trace.tp_print):
-   % if not arg.is_indirect:
+   % if not arg.is_indirect and (arg.length_arg is None or arg.length_arg.isdigit()):
       "${"," if idx != 0 else ""}${arg.name}=${arg.c_format}"
    % endif
    % endfor
       ")"
    % for arg in trace.tp_print:
-   % if not arg.is_indirect:
+   % if not arg.is_indirect and (arg.length_arg is None or arg.length_arg.isdigit()):
       ,${arg.value_expr('entry')}
    % endif
    % endfor
@@ -568,8 +568,9 @@ void __trace_${trace_name}(
   % endfor
    };
  % endif
+   const bool queueing = enabled_traces & U_TRACE_TYPE_REQUIRE_QUEUING;
    UNUSED struct trace_${trace_name} *__entry =
-      enabled_traces & U_TRACE_TYPE_REQUIRE_QUEUING ?
+      queueing ?
       (struct trace_${trace_name} *)u_trace_appendv(ut, ${"cs," if trace.need_cs_param else "NULL,"} &__tp_${trace_name},
                                                     0
   % for arg in trace.tp_struct:
@@ -591,7 +592,10 @@ void __trace_${trace_name}(
   % elif arg.length_arg is None:
      ${arg.copy_func}(__entry->${arg.name}, ${arg.var});
   % else:
-   ${arg.copy_func}(__entry->${arg.name}, ${arg.var}, ${arg.length_arg});
+   % if not arg.length_arg.isdigit():
+   if (queueing)
+   % endif
+     ${arg.copy_func}(__entry->${arg.name}, ${arg.var}, ${arg.length_arg});
   % endif
  % endfor
  % if trace.tp_markers is not None: