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, 78 insertions, 0 deletions

diff --git a/net/bluetooth/msft.h b/net/bluetooth/msft.h
new file mode 100644
index 000000000..fe538e9c9
--- /dev/null
+++ b/net/bluetooth/msft.h
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Google Corporation
+ */
+
+#define MSFT_FEATURE_MASK_BREDR_RSSI_MONITOR		BIT(0)
+#define MSFT_FEATURE_MASK_LE_CONN_RSSI_MONITOR		BIT(1)
+#define MSFT_FEATURE_MASK_LE_ADV_RSSI_MONITOR		BIT(2)
+#define MSFT_FEATURE_MASK_LE_ADV_MONITOR		BIT(3)
+#define MSFT_FEATURE_MASK_CURVE_VALIDITY		BIT(4)
+#define MSFT_FEATURE_MASK_CONCURRENT_ADV_MONITOR	BIT(5)
+
+#if IS_ENABLED(CONFIG_BT_MSFTEXT)
+
+bool msft_monitor_supported(struct hci_dev *hdev);
+void msft_register(struct hci_dev *hdev);
+void msft_release(struct hci_dev *hdev);
+void msft_do_open(struct hci_dev *hdev);
+void msft_do_close(struct hci_dev *hdev);
+void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb);
+__u64 msft_get_features(struct hci_dev *hdev);
+int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor);
+int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor);
+void msft_req_add_set_filter_enable(struct hci_request *req, bool enable);
+int msft_set_filter_enable(struct hci_dev *hdev, bool enable);
+int msft_suspend_sync(struct hci_dev *hdev);
+int msft_resume_sync(struct hci_dev *hdev);
+bool msft_curve_validity(struct hci_dev *hdev);
+
+#else
+
+static inline bool msft_monitor_supported(struct hci_dev *hdev)
+{
+	return false;
+}
+
+static inline void msft_register(struct hci_dev *hdev) {}
+static inline void msft_release(struct hci_dev *hdev) {}
+static inline void msft_do_open(struct hci_dev *hdev) {}
+static inline void msft_do_close(struct hci_dev *hdev) {}
+static inline void msft_vendor_evt(struct hci_dev *hdev, void *data,
+				   struct sk_buff *skb) {}
+static inline __u64 msft_get_features(struct hci_dev *hdev) { return 0; }
+static inline int msft_add_monitor_pattern(struct hci_dev *hdev,
+					   struct adv_monitor *monitor)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int msft_remove_monitor(struct hci_dev *hdev,
+				      struct adv_monitor *monitor)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void msft_req_add_set_filter_enable(struct hci_request *req,
+						  bool enable) {}
+static inline int msft_set_filter_enable(struct hci_dev *hdev, bool enable)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int msft_suspend_sync(struct hci_dev *hdev)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int msft_resume_sync(struct hci_dev *hdev)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline bool msft_curve_validity(struct hci_dev *hdev)
+{
+	return false;
+}
+
+#endif