[VM/Runtime] Cleanup TimelineEventArgument state when it is reused so that there is no stale state when TimelineEventArgument::Free is called.

a-siva · Commit Queue · commit d417da5ed5cf · 2025-07-31T09:26:40.000-07:00
TEST=ci Change-Id: Ia7d7712a4e014b5a330477eac88a61521c19ca25 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/310777 Reviewed-by: Derek Xu <derekx@google.com> Commit-Queue: Siva Annamalai <asiva@google.com>
diff --git a/runtime/vm/timeline.cc b/runtime/vm/timeline.cc
@@ -429,6 +429,8 @@ void TimelineEventArguments::SetNumArguments(intptr_t length) {
   } else {
     for (intptr_t i = length; i < length_; ++i) {
       free(buffer_[i].value);
+      buffer_[i].value = nullptr;
+      buffer_[i].name = nullptr;
     }
     buffer_ = reinterpret_cast<TimelineEventArgument*>(
         realloc(buffer_, sizeof(TimelineEventArgument) * length));

Original file line number	Diff line number	Diff line change
`@@ -429,6 +429,8 @@ void TimelineEventArguments::SetNumArguments(intptr_t length) {`
`429`	`429`	`} else {`
`430`	`430`	`for (intptr_t i = length; i < length_; ++i) {`
`431`	`431`	`free(buffer_[i].value);`
	`432`	`+ buffer_[i].value = nullptr;`
	`433`	`+ buffer_[i].name = nullptr;`
`432`	`434`	`}`
`433`	`435`	`buffer_ = reinterpret_cast<TimelineEventArgument*>(`
`434`	`436`	`realloc(buffer_, sizeof(TimelineEventArgument) * length));`