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, 44 insertions, 0 deletions

diff --git a/drivers/md/md-cluster.h b/drivers/md/md-cluster.h
new file mode 100644
index 000000000..8fb06d853
--- /dev/null
+++ b/drivers/md/md-cluster.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+
+#ifndef _MD_CLUSTER_H
+#define _MD_CLUSTER_H
+
+#include "md.h"
+
+struct mddev;
+struct md_rdev;
+
+struct md_cluster_operations {
+	struct md_submodule_head head;
+
+	int (*join)(struct mddev *mddev, int nodes);
+	int (*leave)(struct mddev *mddev);
+	int (*slot_number)(struct mddev *mddev);
+	int (*resync_info_update)(struct mddev *mddev, sector_t lo, sector_t hi);
+	int (*resync_start_notify)(struct mddev *mddev);
+	int (*resync_status_get)(struct mddev *mddev);
+	void (*resync_info_get)(struct mddev *mddev, sector_t *lo, sector_t *hi);
+	int (*metadata_update_start)(struct mddev *mddev);
+	int (*metadata_update_finish)(struct mddev *mddev);
+	void (*metadata_update_cancel)(struct mddev *mddev);
+	int (*resync_start)(struct mddev *mddev);
+	int (*resync_finish)(struct mddev *mddev);
+	int (*area_resyncing)(struct mddev *mddev, int direction, sector_t lo, sector_t hi);
+	int (*add_new_disk)(struct mddev *mddev, struct md_rdev *rdev);
+	void (*add_new_disk_cancel)(struct mddev *mddev);
+	int (*new_disk_ack)(struct mddev *mddev, bool ack);
+	int (*remove_disk)(struct mddev *mddev, struct md_rdev *rdev);
+	void (*load_bitmaps)(struct mddev *mddev, int total_slots);
+	int (*gather_bitmaps)(struct md_rdev *rdev);
+	int (*resize_bitmaps)(struct mddev *mddev, sector_t newsize, sector_t oldsize);
+	int (*lock_all_bitmaps)(struct mddev *mddev);
+	void (*unlock_all_bitmaps)(struct mddev *mddev);
+	void (*update_size)(struct mddev *mddev, sector_t old_dev_sectors);
+};
+
+extern int md_setup_cluster(struct mddev *mddev, int nodes);
+extern void md_cluster_stop(struct mddev *mddev);
+extern void md_reload_sb(struct mddev *mddev, int raid_disk);
+
+#endif /* _MD_CLUSTER_H */