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, 24 insertions, 0 deletions

diff --git a/tools/perf/ui/util.h b/tools/perf/ui/util.h
new file mode 100644
index 000000000..e30cea807
--- /dev/null
+++ b/tools/perf/ui/util.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PERF_UI_UTIL_H_
+#define _PERF_UI_UTIL_H_ 1
+
+#include <stdarg.h>
+
+int ui__getch(int delay_secs);
+int ui__popup_menu(int argc, char * const argv[], int *keyp);
+int ui__help_window(const char *text);
+int ui__dialog_yesno(const char *msg);
+void __ui__info_window(const char *title, const char *text, const char *exit_msg);
+void ui__info_window(const char *title, const char *text);
+int ui__question_window(const char *title, const char *text,
+			const char *exit_msg, int delay_secs);
+
+struct perf_error_ops {
+	int (*error)(const char *format, va_list args);
+	int (*warning)(const char *format, va_list args);
+};
+
+int perf_error__register(struct perf_error_ops *eops);
+int perf_error__unregister(struct perf_error_ops *eops);
+
+#endif /* _PERF_UI_UTIL_H_ */