ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/net/rfkill/rfkill.h b/net/rfkill/rfkill.h
new file mode 100644
index 000000000..001c40caa
--- /dev/null
+++ b/net/rfkill/rfkill.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2007 Ivo van Doorn
+ * Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
+ */
+
+
+#ifndef __RFKILL_INPUT_H
+#define __RFKILL_INPUT_H
+
+/* core code */
+void rfkill_switch_all(const enum rfkill_type type, bool blocked);
+void rfkill_epo(void);
+void rfkill_restore_states(void);
+void rfkill_remove_epo_lock(void);
+bool rfkill_is_epo_lock_active(void);
+bool rfkill_get_global_sw_state(const enum rfkill_type type);
+
+/* input handler */
+int rfkill_handler_init(void);
+void rfkill_handler_exit(void);
+
+#endif /* __RFKILL_INPUT_H */