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, 55 insertions, 0 deletions

diff --git a/drivers/usb/image/microtek.h b/drivers/usb/image/microtek.h
new file mode 100644
index 000000000..7bd5f4639
--- /dev/null
+++ b/drivers/usb/image/microtek.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+ /*
+ * Driver for Microtek Scanmaker X6 USB scanner and possibly others.
+ * 
+ * (C) Copyright 2000 John Fremlin <vii@penguinpowered.com>
+ * (C) Copyright 2000 Oliver Neukum <Oliver.Neukum@lrz.uni-muenchen.de>
+ *
+ * See microtek.c for history
+ *
+ */
+
+typedef void (*mts_scsi_cmnd_callback)(struct scsi_cmnd *);
+
+
+struct mts_transfer_context
+{
+	struct mts_desc *instance;
+	mts_scsi_cmnd_callback final_callback;
+	struct scsi_cmnd *srb;
+	
+	void *data;
+	unsigned data_length;
+	int data_pipe;
+	struct scatterlist *curr_sg;
+
+	u8 *scsi_status; /* status returned from ep_response after command completion */
+};
+
+
+struct mts_desc {
+	struct mts_desc *next;
+	struct mts_desc *prev;
+
+	struct usb_device *usb_dev;
+	struct usb_interface *usb_intf;
+
+	/* Endpoint addresses */
+	u8 ep_out;
+	u8 ep_response;
+	u8 ep_image;
+
+	struct Scsi_Host *host;
+
+	struct urb *urb;
+	struct mts_transfer_context context;
+};
+
+
+#define MTS_EP_OUT	0x1
+#define MTS_EP_RESPONSE	0x2
+#define MTS_EP_IMAGE	0x3
+#define MTS_EP_TOTAL	0x3
+
+#define MTS_SCSI_ERR_MASK ~0x3fu
+