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, 72 insertions, 0 deletions

diff --git a/drivers/pci/controller/pci-host-common.h b/drivers/pci/controller/pci-host-common.h
new file mode 100644
index 000000000..51afd65d3
--- /dev/null
+++ b/drivers/pci/controller/pci-host-common.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common library for PCI host controller drivers
+ *
+ * Copyright (C) 2014 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#ifndef _PCI_HOST_COMMON_H
+#define _PCI_HOST_COMMON_H
+
+#include <linux/delay.h>
+#include "../pci.h"
+
+struct pci_ecam_ops;
+
+/**
+ * struct pci_host_perst - PERST# GPIO descriptor
+ * @list: List node for linking multiple PERST# GPIOs
+ * @desc: GPIO descriptor for PERST# signal
+ *
+ * This structure holds a single PERST# GPIO descriptor.
+ */
+struct pci_host_perst {
+	struct list_head	list;
+	struct gpio_desc	*desc;
+};
+
+/**
+ * struct pci_host_port - Generic Root Port properties
+ * @list: List node for linking multiple ports
+ * @perst: List of PERST# GPIO descriptors for this port and its children
+ *
+ * This structure contains common properties that can be parsed from
+ * Root Port device tree nodes.
+ */
+struct pci_host_port {
+	struct list_head	list;
+	struct list_head	perst;
+};
+
+void pci_host_common_delete_ports(void *data);
+int pci_host_common_parse_ports(struct device *dev,
+				struct pci_host_bridge *bridge);
+int pci_host_common_probe(struct platform_device *pdev);
+int pci_host_common_init(struct platform_device *pdev,
+			 struct pci_host_bridge *bridge,
+			 const struct pci_ecam_ops *ops);
+void pci_host_common_remove(struct platform_device *pdev);
+void pci_host_handle_link_down(struct pci_dev *port);
+
+struct pci_config_window *pci_host_common_ecam_create(struct device *dev,
+	struct pci_host_bridge *bridge, const struct pci_ecam_ops *ops);
+
+bool pci_host_common_d3cold_possible(struct pci_host_bridge *bridge,
+				     bool *pme_capable);
+
+/**
+ * pci_host_common_link_train_delay - Wait 100 ms if link speed > 5 GT/s
+ * @max_link_speed: the maximum link speed (2 = 5.0 GT/s, 3 = 8.0 GT/s, ...)
+ *
+ * Must be called after Link training completes and before the first
+ * Configuration Request is sent.
+ */
+static inline void pci_host_common_link_train_delay(int max_link_speed)
+{
+	if (max_link_speed > 2)
+		msleep(PCIE_RESET_CONFIG_WAIT_MS);
+}
+
+#endif