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, 53 insertions, 0 deletions

diff --git a/drivers/nfc/mei_phy.h b/drivers/nfc/mei_phy.h
new file mode 100644
index 000000000..9b9c5eb54
--- /dev/null
+++ b/drivers/nfc/mei_phy.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LOCAL_MEI_PHY_H_
+#define __LOCAL_MEI_PHY_H_
+
+#include <linux/mei_cl_bus.h>
+#include <net/nfc/hci.h>
+#include <linux/uuid.h>
+
+#define MEI_NFC_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, \
+		0x94, 0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c)
+#define MEI_NFC_HEADER_SIZE 10
+#define MEI_NFC_MAX_HCI_PAYLOAD 300
+
+/**
+ * struct nfc_mei_phy - NFC description of the MEI PHY and interface functions
+ *
+ * @cldev: mei client device
+ * @hdev:   nfc hci device
+ *
+ * @send_wq: send completion wait queue
+ * @fw_ivn: NFC Interface Version Number
+ * @vendor_id: NFC manufacturer ID
+ * @radio_type: NFC radio type
+ * @reserved: reserved for alignment
+ * @req_id:  message counter
+ * @recv_req_id: reception message counter
+ * @powered: the device is in powered state
+ * @hard_fault: < 0 if hardware error occurred
+ *    and prevents normal operation.
+ */
+struct nfc_mei_phy {
+	struct mei_cl_device *cldev;
+	struct nfc_hci_dev *hdev;
+
+	wait_queue_head_t send_wq;
+	u8 fw_ivn;
+	u8 vendor_id;
+	u8 radio_type;
+	u8 reserved;
+
+	u16 req_id;
+	u16 recv_req_id;
+
+	int powered;
+	int hard_fault;
+};
+
+extern const struct nfc_phy_ops mei_phy_ops;
+
+struct nfc_mei_phy *nfc_mei_phy_alloc(struct mei_cl_device *device);
+void nfc_mei_phy_free(struct nfc_mei_phy *phy);
+
+#endif /* __LOCAL_MEI_PHY_H_ */