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, 132 insertions, 0 deletions

diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
new file mode 100644
index 000000000..b88b01aa5
--- /dev/null
+++ b/drivers/cpuidle/Kconfig.arm
@@ -0,0 +1,132 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# ARM CPU Idle drivers
+#
+config ARM_CPUIDLE
+	bool "Generic ARM CPU idle Driver"
+	depends on ARM
+	select DT_IDLE_STATES
+	select CPU_IDLE_MULTIPLE_DRIVERS
+	help
+	  Select this to enable generic cpuidle driver for ARM.
+	  It provides a generic idle driver whose idle states are configured
+	  at run-time through DT nodes. The CPUidle suspend backend is
+	  initialized by calling the CPU operations init idle hook
+	  provided by architecture code.
+
+config ARM_PSCI_CPUIDLE
+	bool "PSCI CPU idle Driver"
+	depends on ARM_PSCI_FW
+	select DT_IDLE_STATES
+	select CPU_IDLE_MULTIPLE_DRIVERS
+	help
+	  Select this to enable PSCI firmware based CPUidle driver for ARM.
+	  It provides an idle driver that is capable of detecting and
+	  managing idle states through the PSCI firmware interface.
+
+	  The driver has limitations when used with PREEMPT_RT:
+	  - If the idle states are described with the non-hierarchical layout,
+	    all idle states are still available.
+
+	  - If the idle states are described with the hierarchical layout,
+	    only the idle states defined per CPU are available, but not the ones
+	    being shared among a group of CPUs (aka cluster idle states).
+
+config ARM_PSCI_CPUIDLE_DOMAIN
+	bool "PSCI CPU idle Domain"
+	depends on ARM_PSCI_CPUIDLE
+	depends on PM_GENERIC_DOMAINS_OF
+	select DT_IDLE_GENPD
+	default y
+	help
+	  Select this to enable the PSCI based CPUidle driver to use PM domains,
+	  which is needed to support the hierarchical DT based layout of the
+	  idle states.
+
+config ARM_BIG_LITTLE_CPUIDLE
+	bool "Support for ARM big.LITTLE processors"
+	depends on ARCH_VEXPRESS_TC2_PM || ARCH_EXYNOS || COMPILE_TEST
+	depends on MCPM && !ARM64
+	select ARM_CPU_SUSPEND
+	select CPU_IDLE_MULTIPLE_DRIVERS
+	select DT_IDLE_STATES
+	help
+	  Select this option to enable CPU idle driver for big.LITTLE based
+	  ARM systems. Driver manages CPUs coordination through MCPM and
+	  define different C-states for little and big cores through the
+	  multiple CPU idle drivers infrastructure.
+
+config ARM_CLPS711X_CPUIDLE
+	bool "CPU Idle Driver for CLPS711X processors"
+	depends on ARCH_CLPS711X && !ARM64 || COMPILE_TEST
+	help
+	  Select this to enable cpuidle on Cirrus Logic CLPS711X SOCs.
+
+config ARM_HIGHBANK_CPUIDLE
+	bool "CPU Idle Driver for Calxeda processors"
+	depends on ARM_PSCI && !ARM64
+	select ARM_CPU_SUSPEND
+	help
+	  Select this to enable cpuidle on Calxeda processors.
+
+config ARM_KIRKWOOD_CPUIDLE
+	bool "CPU Idle Driver for Marvell Kirkwood SoCs"
+	depends on (MACH_KIRKWOOD || COMPILE_TEST) && !ARM64
+	help
+	  This adds the CPU Idle driver for Marvell Kirkwood SoCs.
+
+config ARM_ZYNQ_CPUIDLE
+	bool "CPU Idle Driver for Xilinx Zynq processors"
+	depends on (ARCH_ZYNQ || COMPILE_TEST) && !ARM64
+	help
+	  Select this to enable cpuidle on Xilinx Zynq processors.
+
+config ARM_U8500_CPUIDLE
+	bool "Cpu Idle Driver for the ST-E u8500 processors"
+	depends on ARCH_U8500 && !ARM64
+	help
+	  Select this to enable cpuidle for ST-E u8500 processors.
+
+config ARM_AT91_CPUIDLE
+	bool "Cpu Idle Driver for the AT91 processors"
+	default y
+	depends on (ARCH_AT91 || COMPILE_TEST) && !ARM64
+	help
+	  Select this to enable cpuidle for AT91 processors.
+
+config ARM_EXYNOS_CPUIDLE
+	bool "Cpu Idle Driver for the Exynos processors"
+	depends on (ARCH_EXYNOS || COMPILE_TEST) && !ARM64
+	select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
+	help
+	  Select this to enable cpuidle for Exynos processors.
+
+config ARM_MVEBU_V7_CPUIDLE
+	bool "CPU Idle Driver for mvebu v7 family processors"
+	depends on (ARCH_MVEBU || COMPILE_TEST) && !ARM64
+	help
+	  Select this to enable cpuidle on Armada 370, 38x and XP processors.
+
+config ARM_TEGRA_CPUIDLE
+	bool "CPU Idle Driver for NVIDIA Tegra SoCs"
+	depends on (ARCH_TEGRA || COMPILE_TEST) && !ARM64 && MMU
+	depends on ARCH_SUSPEND_POSSIBLE
+	select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
+	select ARM_CPU_SUSPEND
+	help
+	  Select this to enable cpuidle for NVIDIA Tegra20/30/114/124 SoCs.
+
+config ARM_QCOM_SPM_CPUIDLE
+	bool "CPU Idle Driver for Qualcomm Subsystem Power Manager (SPM)"
+	depends on (ARCH_QCOM || COMPILE_TEST) && !ARM64 && MMU
+	depends on ARCH_SUSPEND_POSSIBLE
+	depends on QCOM_SCM=y
+	depends on QCOM_SPM=y
+	select ARM_CPU_SUSPEND
+	select CPU_IDLE_MULTIPLE_DRIVERS
+	select DT_IDLE_STATES
+	help
+	  Select this to enable cpuidle for Qualcomm processors.
+	  The Subsystem Power Manager (SPM) controls low power modes for the
+	  CPU and L2 cores. It interface with various system drivers to put
+	  the cores in low power modes.