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, 186 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/Kconfig b/drivers/pci/hotplug/Kconfig
new file mode 100644
index 000000000..3207860b5
--- /dev/null
+++ b/drivers/pci/hotplug/Kconfig
@@ -0,0 +1,186 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# PCI Hotplug support
+#
+
+menuconfig HOTPLUG_PCI
+	bool "Support for PCI Hotplug"
+	depends on PCI && SYSFS
+	default y if USB4
+	help
+	  Say Y here if you have a motherboard with a PCI Hotplug controller.
+	  This allows you to add and remove PCI cards while the machine is
+	  powered up and running.
+
+	  Thunderbolt/USB4 PCIe tunneling depends on native PCIe hotplug.
+
+	  When in doubt, say N.
+
+if HOTPLUG_PCI
+
+config HOTPLUG_PCI_COMPAQ
+	tristate "Compaq PCI Hotplug driver"
+	depends on X86 && PCI_BIOS
+	help
+	  Say Y here if you have a motherboard with a Compaq PCI Hotplug
+	  controller.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cpqphp.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_COMPAQ_NVRAM
+	bool "Save configuration into NVRAM on Compaq servers"
+	depends on HOTPLUG_PCI_COMPAQ
+	help
+	  Say Y here if you have a Compaq server that has a PCI Hotplug
+	  controller.  This will allow the PCI Hotplug driver to store the PCI
+	  system configuration options in NVRAM.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_IBM
+	tristate "IBM PCI Hotplug driver"
+	depends on X86_IO_APIC && X86 && PCI_BIOS
+	help
+	  Say Y here if you have a motherboard with a IBM PCI Hotplug
+	  controller.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ibmphp.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_ACPI
+	bool "ACPI PCI Hotplug driver"
+	depends on HOTPLUG_PCI=y && ((!ACPI_DOCK && ACPI) || (ACPI_DOCK))
+	help
+	  Say Y here if you have a system that supports PCI Hotplug using
+	  ACPI.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_ACPI_AMPERE_ALTRA
+	tristate "ACPI PCI Hotplug driver Ampere Altra extensions"
+	depends on HOTPLUG_PCI_ACPI
+	depends on HAVE_ARM_SMCCC_DISCOVERY
+	help
+	  Say Y here if you have an Ampere Altra system.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called acpiphp_ampere_altra.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_ACPI_IBM
+	tristate "ACPI PCI Hotplug driver IBM extensions"
+	depends on HOTPLUG_PCI_ACPI
+	help
+	  Say Y here if you have an IBM system that supports PCI Hotplug using
+	  ACPI.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called acpiphp_ibm.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_CPCI
+	bool "CompactPCI Hotplug driver"
+	help
+	  Say Y here if you have a CompactPCI system card with CompactPCI
+	  hotswap support per the PICMG 2.1 specification.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_CPCI_ZT5550
+	tristate "Ziatech ZT5550 CompactPCI Hotplug driver"
+	depends on HOTPLUG_PCI_CPCI && X86
+	help
+	  Say Y here if you have a Performance Technologies (formerly Intel,
+	  formerly just Ziatech) Ziatech ZT5550 CompactPCI system card.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cpcihp_zt5550.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_CPCI_GENERIC
+	tristate "Generic port I/O CompactPCI Hotplug driver"
+	depends on HOTPLUG_PCI_CPCI && X86
+	help
+	  Say Y here if you have a CompactPCI system card that exposes the #ENUM
+	  hotswap signal as a bit in a system register that can be read through
+	  standard port I/O.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cpcihp_generic.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_OCTEONEP
+	bool "Marvell OCTEON PCI Hotplug driver"
+	depends on HOTPLUG_PCI
+	help
+	  Say Y here if you have an OCTEON PCIe device with a hotplug
+	  controller. This driver enables the non-controller functions of the
+	  device to be registered as hotplug slots.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_SHPC
+	bool "SHPC PCI Hotplug driver"
+	help
+	  Say Y here if you have a motherboard with a SHPC PCI Hotplug
+	  controller.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_POWERNV
+	tristate "PowerPC PowerNV PCI Hotplug driver"
+	depends on PPC_POWERNV && EEH
+	select OF_DYNAMIC
+	help
+	  Say Y here if you run PowerPC PowerNV platform that supports
+	  PCI Hotplug
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pnv-php.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_RPA
+	tristate "RPA PCI Hotplug driver"
+	depends on PPC_PSERIES && EEH
+	help
+	  Say Y here if you have a RPA system that supports PCI Hotplug.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rpaphp.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_RPA_DLPAR
+	tristate "RPA Dynamic Logical Partitioning for I/O slots"
+	depends on HOTPLUG_PCI_RPA
+	help
+	  Say Y here if your system supports Dynamic Logical Partitioning
+	  for I/O slots.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rpadlpar_io.
+
+	  When in doubt, say N.
+
+config HOTPLUG_PCI_S390
+	bool "System z PCI Hotplug Support"
+	depends on S390 && 64BIT
+	help
+	  Say Y here if you want to use the System z PCI Hotplug
+	  driver for PCI devices. Without this driver it is not
+	  possible to access stand-by PCI functions nor to deconfigure
+	  PCI functions.
+
+	  When in doubt, say Y.
+
+endif # HOTPLUG_PCI