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, 286 insertions, 0 deletions

diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h
new file mode 100644
index 000000000..031114478
--- /dev/null
+++ b/drivers/misc/mei/client.h
@@ -0,0 +1,286 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2003-2018, Intel Corporation. All rights reserved.
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ */
+
+#ifndef _MEI_CLIENT_H_
+#define _MEI_CLIENT_H_
+
+#include <linux/types.h>
+#include <linux/poll.h>
+#include <linux/mei.h>
+
+#include "mei_dev.h"
+
+/*
+ * reference counting base function
+ */
+void mei_me_cl_init(struct mei_me_client *me_cl);
+void mei_me_cl_put(struct mei_me_client *me_cl);
+struct mei_me_client *mei_me_cl_get(struct mei_me_client *me_cl);
+
+void mei_me_cl_add(struct mei_device *dev, struct mei_me_client *me_cl);
+void mei_me_cl_del(struct mei_device *dev, struct mei_me_client *me_cl);
+
+struct mei_me_client *mei_me_cl_by_uuid(struct mei_device *dev,
+					const uuid_le *uuid);
+struct mei_me_client *mei_me_cl_by_id(struct mei_device *dev, u8 client_id);
+struct mei_me_client *mei_me_cl_by_uuid_id(struct mei_device *dev,
+					   const uuid_le *uuid, u8 client_id);
+void mei_me_cl_rm_by_uuid(struct mei_device *dev, const uuid_le *uuid);
+void mei_me_cl_rm_all(struct mei_device *dev);
+
+/**
+ * mei_me_cl_is_active - check whether me client is active in the fw
+ *
+ * @me_cl: me client
+ *
+ * Return: true if the me client is active in the firmware
+ */
+static inline bool mei_me_cl_is_active(const struct mei_me_client *me_cl)
+{
+	return !list_empty_careful(&me_cl->list);
+}
+
+/**
+ * mei_me_cl_uuid - return me client protocol name (uuid)
+ *
+ * @me_cl: me client
+ *
+ * Return: me client protocol name
+ */
+static inline const uuid_le *mei_me_cl_uuid(const struct mei_me_client *me_cl)
+{
+	return &me_cl->props.protocol_name;
+}
+
+/**
+ * mei_me_cl_ver - return me client protocol version
+ *
+ * @me_cl: me client
+ *
+ * Return: me client protocol version
+ */
+static inline u8 mei_me_cl_ver(const struct mei_me_client *me_cl)
+{
+	return me_cl->props.protocol_version;
+}
+
+/**
+ * mei_me_cl_max_conn - return me client max number of connections
+ *
+ * @me_cl: me client
+ *
+ * Return: me client max number of connections
+ */
+static inline u8 mei_me_cl_max_conn(const struct mei_me_client *me_cl)
+{
+	return me_cl->props.max_number_of_connections;
+}
+
+/**
+ * mei_me_cl_fixed - return me client fixed address, if any
+ *
+ * @me_cl: me client
+ *
+ * Return: me client fixed address
+ */
+static inline u8 mei_me_cl_fixed(const struct mei_me_client *me_cl)
+{
+	return me_cl->props.fixed_address;
+}
+
+/**
+ * mei_me_cl_vt - return me client vtag supported status
+ *
+ * @me_cl: me client
+ *
+ * Return: true if me client supports vt tagging
+ */
+static inline bool mei_me_cl_vt(const struct mei_me_client *me_cl)
+{
+	return me_cl->props.vt_supported == 1;
+}
+
+/**
+ * mei_me_cl_max_len - return me client max msg length
+ *
+ * @me_cl: me client
+ *
+ * Return: me client max msg length
+ */
+static inline u32 mei_me_cl_max_len(const struct mei_me_client *me_cl)
+{
+	return me_cl->props.max_msg_length;
+}
+
+/*
+ * MEI IO Functions
+ */
+void mei_io_cb_free(struct mei_cl_cb *priv_cb);
+
+/*
+ * MEI Host Client Functions
+ */
+
+struct mei_cl *mei_cl_allocate(struct mei_device *dev);
+
+int mei_cl_link(struct mei_cl *cl);
+int mei_cl_unlink(struct mei_cl *cl);
+
+struct mei_cl *mei_cl_alloc_linked(struct mei_device *dev);
+
+struct mei_cl_cb *mei_cl_read_cb(struct mei_cl *cl, const struct file *fp);
+
+void mei_cl_add_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb);
+void mei_cl_del_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb);
+
+struct mei_cl_cb *mei_cl_alloc_cb(struct mei_cl *cl, size_t length,
+				  enum mei_cb_file_ops type,
+				  const struct file *fp);
+struct mei_cl_cb *mei_cl_enqueue_ctrl_wr_cb(struct mei_cl *cl, size_t length,
+					    enum mei_cb_file_ops type,
+					    const struct file *fp);
+int mei_cl_flush_queues(struct mei_cl *cl, const struct file *fp);
+
+struct mei_cl_vtag *mei_cl_vtag_alloc(struct file *fp, u8 vtag);
+const struct file *mei_cl_fp_by_vtag(const struct mei_cl *cl, u8 vtag);
+int mei_cl_vt_support_check(const struct mei_cl *cl);
+/*
+ *  MEI input output function prototype
+ */
+
+/**
+ * mei_cl_is_connected - host client is connected
+ *
+ * @cl: host client
+ *
+ * Return: true if the host client is connected
+ */
+static inline bool mei_cl_is_connected(const struct mei_cl *cl)
+{
+	return  cl->state == MEI_FILE_CONNECTED;
+}
+
+/**
+ * mei_cl_me_id - me client id
+ *
+ * @cl: host client
+ *
+ * Return: me client id or 0 if client is not connected
+ */
+static inline u8 mei_cl_me_id(const struct mei_cl *cl)
+{
+	return cl->me_cl ? cl->me_cl->client_id : 0;
+}
+
+/**
+ * mei_cl_mtu - maximal message that client can send and receive
+ *
+ * @cl: host client
+ *
+ * Return: mtu or 0 if client is not connected
+ */
+static inline size_t mei_cl_mtu(const struct mei_cl *cl)
+{
+	return cl->me_cl ? cl->me_cl->props.max_msg_length : 0;
+}
+
+/**
+ * mei_cl_is_fixed_address - check whether the me client uses fixed address
+ *
+ * @cl: host client
+ *
+ * Return: true if the client is connected and it has fixed me address
+ */
+static inline bool mei_cl_is_fixed_address(const struct mei_cl *cl)
+{
+	return cl->me_cl && cl->me_cl->props.fixed_address;
+}
+
+/**
+ * mei_cl_is_single_recv_buf- check whether the me client
+ *       uses single receiving buffer
+ *
+ * @cl: host client
+ *
+ * Return: true if single_recv_buf == 1; 0 otherwise
+ */
+static inline bool mei_cl_is_single_recv_buf(const struct mei_cl *cl)
+{
+	return cl->me_cl->props.single_recv_buf;
+}
+
+/**
+ * mei_cl_uuid -  client's uuid
+ *
+ * @cl: host client
+ *
+ * Return: return uuid of connected me client
+ */
+static inline const uuid_le *mei_cl_uuid(const struct mei_cl *cl)
+{
+	return mei_me_cl_uuid(cl->me_cl);
+}
+
+/**
+ * mei_cl_host_addr - client's host address
+ *
+ * @cl: host client
+ *
+ * Return: 0 for fixed address client, host address for dynamic client
+ */
+static inline u8 mei_cl_host_addr(const struct mei_cl *cl)
+{
+	return  mei_cl_is_fixed_address(cl) ? 0 : cl->host_client_id;
+}
+
+int mei_cl_disconnect(struct mei_cl *cl);
+int mei_cl_irq_disconnect(struct mei_cl *cl, struct mei_cl_cb *cb,
+			  struct list_head *cmpl_list);
+int mei_cl_connect(struct mei_cl *cl, struct mei_me_client *me_cl,
+		   const struct file *file);
+int mei_cl_irq_connect(struct mei_cl *cl, struct mei_cl_cb *cb,
+		       struct list_head *cmpl_list);
+int mei_cl_read_start(struct mei_cl *cl, size_t length, const struct file *fp);
+ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, unsigned long timeout);
+int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
+		     struct list_head *cmpl_list);
+
+void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb);
+
+void mei_host_client_init(struct mei_device *dev);
+
+u8 mei_cl_notify_fop2req(enum mei_cb_file_ops fop);
+enum mei_cb_file_ops mei_cl_notify_req2fop(u8 request);
+int mei_cl_notify_request(struct mei_cl *cl,
+			  const struct file *file, u8 request);
+int mei_cl_irq_notify(struct mei_cl *cl, struct mei_cl_cb *cb,
+		      struct list_head *cmpl_list);
+int mei_cl_notify_get(struct mei_cl *cl, bool block, bool *notify_ev);
+void mei_cl_notify(struct mei_cl *cl);
+
+void mei_cl_all_disconnect(struct mei_device *dev);
+
+int mei_cl_irq_dma_map(struct mei_cl *cl, struct mei_cl_cb *cb,
+		       struct list_head *cmpl_list);
+int mei_cl_irq_dma_unmap(struct mei_cl *cl, struct mei_cl_cb *cb,
+			 struct list_head *cmpl_list);
+int mei_cl_dma_alloc_and_map(struct mei_cl *cl, const struct file *fp,
+			     u8 buffer_id, size_t size);
+int mei_cl_dma_unmap(struct mei_cl *cl, const struct file *fp);
+
+#define MEI_CL_FMT "cl:host=%02d me=%02d "
+#define MEI_CL_PRM(cl) (cl)->host_client_id, mei_cl_me_id(cl)
+
+#define cl_dbg(dev, cl, format, arg...) \
+	dev_dbg(&(dev)->dev, MEI_CL_FMT format, MEI_CL_PRM(cl), ##arg)
+
+#define cl_warn(dev, cl, format, arg...) \
+	dev_warn(&(dev)->dev, MEI_CL_FMT format, MEI_CL_PRM(cl), ##arg)
+
+#define cl_err(dev, cl, format, arg...) \
+	dev_err(&(dev)->dev, MEI_CL_FMT format, MEI_CL_PRM(cl), ##arg)
+
+#endif /* _MEI_CLIENT_H_ */