From d7dbdd2ee01e12211046d4a535623ac732b749fb Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Fri, 4 Sep 2026 08:25:04 +0900 Subject: [PATCH] tracing: Fix to avoid creating trace instances with duplicate names Since commit e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") changed trace_array_get_by_name() to trace_array_create_systems(), enable_instances() does not reuse the same name instance. Therefore, if an administrator mistakenly specifies multiple `trace_instance=` options with duplicate names, all are created but only the first is accessible via tracefs. Check whether an instance with the same name already exists before creating a new one, and reject duplicates with a warning. Link: https://patch.msgid.link/178847790399.283263.5313150997200138426.stgit@devnote2 Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 722d0ba2d233..138e983c3c2f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9710,6 +9710,11 @@ __init static void enable_instances(void) if (flag_delim) *flag_delim++ = '\0'; + if (trace_array_find(name)) { + pr_warn("Tracing: Instance %s already exists\n", name); + continue; + } + if (backup) { if (backup_instance_area(backup, &addr, &size) < 0) continue;