ftrace: Add sanity check when unregistering last ftrace_ops

When the last ftrace_ops is unregistered, all the function records should
have a zeroed flags value. Make sure that is the case when the last ftrace_ops
is unregistered.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d325a1e76554..fb186b9ddf51 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2416,6 +2416,21 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 
         ftrace_run_update_code(command);
 
+        /*
+         * If there's no more ops registered with ftrace, run a
+         * sanity check to make sure all rec flags are cleared.
+         */
+        if (ftrace_ops_list == &ftrace_list_end) {
+                struct ftrace_page *pg;
+                struct dyn_ftrace *rec;
+
+                do_for_each_ftrace_rec(pg, rec) {
+                        if (FTRACE_WARN_ON_ONCE(rec->flags))
+                                pr_warn("  %pS flags:%lx\n",
+                                        (void *)rec->ip, rec->flags);
+                } while_for_each_ftrace_rec();
+        }
+
         ops->old_hash.filter_hash = NULL;
         ops->old_hash.notrace_hash = NULL;