From: Masami Hiramatsu (Google) <[email protected]>
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.
Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace
boot instance")
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
---
kernel/trace/trace.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a946e0183fd1..536e71f28d51 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9651,6 +9651,11 @@ __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;
