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, 37 insertions, 0 deletions

diff --git a/tools/perf/ui/ui.h b/tools/perf/ui/ui.h
new file mode 100644
index 000000000..d8e911205
--- /dev/null
+++ b/tools/perf/ui/ui.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PERF_UI_H_
+#define _PERF_UI_H_ 1
+
+#include "../util/mutex.h"
+#include <stdbool.h>
+#include <linux/compiler.h>
+
+extern struct mutex ui__lock;
+extern void *perf_gtk_handle;
+
+extern int use_browser;
+
+void setup_browser(bool fallback_to_pager);
+void exit_browser(bool wait_for_ok);
+
+#ifdef HAVE_SLANG_SUPPORT
+int ui__init(void);
+void ui__exit(bool wait_for_ok);
+#else
+static inline int ui__init(void)
+{
+	return -1;
+}
+static inline void ui__exit(bool wait_for_ok __maybe_unused) {}
+#endif
+
+void ui__refresh_dimensions(bool force);
+
+struct option;
+
+int stdio__config_color(const struct option *opt, const char *mode, int unset);
+
+void pthread__block_sigwinch(void);
+void pthread__unblock_sigwinch(void);
+
+#endif /* _PERF_UI_H_ */