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, 117 insertions, 0 deletions

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
new file mode 100644
index 000000000..652557a5b
--- /dev/null
+++ b/drivers/iio/Kconfig
@@ -0,0 +1,117 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Industrial I/O subsystem configuration
+#
+
+menuconfig IIO
+	tristate "Industrial I/O support"
+	help
+	  The industrial I/O subsystem provides a unified framework for
+	  drivers for many different types of embedded sensors using a
+	  number of different physical interfaces (i2c, spi, etc).
+
+if IIO
+
+config IIO_BUFFER
+	bool "Enable buffer support within IIO"
+	select DMA_SHARED_BUFFER
+	help
+	  Provide core support for various buffer based data
+	  acquisition methods.
+
+if IIO_BUFFER
+	source "drivers/iio/buffer/Kconfig"
+endif # IIO_BUFFER
+
+config IIO_CONFIGFS
+	tristate "Enable IIO configuration via configfs"
+	select CONFIGFS_FS
+	help
+	  This allows configuring various IIO bits through configfs
+	  (e.g. software triggers). For more info see
+	  Documentation/iio/iio_configfs.rst.
+
+config IIO_GTS_HELPER
+	tristate
+
+config IIO_TRIGGER
+	bool "Enable triggered sampling support"
+	help
+	  Provides IIO core support for triggers.  Currently these
+	  are used to initialize capture of samples to push into
+	  buffers.  The triggers are effectively a 'capture
+	  data now' interrupt.
+
+config IIO_CONSUMERS_PER_TRIGGER
+	int "Maximum number of consumers per trigger"
+	depends on IIO_TRIGGER
+	default "2"
+	help
+	  This value controls the maximum number of consumers that a
+	  given trigger may handle. Default is 2.
+
+config IIO_SW_DEVICE
+	tristate "Enable software IIO device support"
+	select IIO_CONFIGFS
+	help
+	  Provides IIO core support for software devices. A software
+	  device can be created via configfs or directly by a driver
+	  using the API provided.
+
+config IIO_SW_TRIGGER
+	tristate "Enable software triggers support"
+	select IIO_CONFIGFS
+	help
+	  Provides IIO core support for software triggers. A software
+	  trigger can be created via configfs or directly by a driver
+	  using the API provided.
+
+config IIO_TRIGGERED_EVENT
+	tristate "Enable triggered events support"
+	select IIO_TRIGGER
+	help
+	  Provides helper functions for setting up triggered events.
+
+config IIO_BACKEND
+	tristate
+	help
+	  Framework to handle complex IIO aggregate devices. The typical
+	  architecture that can make use of this framework is to have one
+	  device as the frontend device which can be "linked" against one or
+	  multiple backend devices. The framework then makes it easy to get
+	  and control such backend devices.
+
+source "drivers/iio/accel/Kconfig"
+source "drivers/iio/adc/Kconfig"
+source "drivers/iio/addac/Kconfig"
+source "drivers/iio/afe/Kconfig"
+source "drivers/iio/amplifiers/Kconfig"
+source "drivers/iio/cdc/Kconfig"
+source "drivers/iio/chemical/Kconfig"
+source "drivers/iio/common/Kconfig"
+source "drivers/iio/dac/Kconfig"
+source "drivers/iio/dummy/Kconfig"
+source "drivers/iio/filter/Kconfig"
+source "drivers/iio/flow/Kconfig"
+source "drivers/iio/frequency/Kconfig"
+source "drivers/iio/gyro/Kconfig"
+source "drivers/iio/health/Kconfig"
+source "drivers/iio/humidity/Kconfig"
+source "drivers/iio/imu/Kconfig"
+source "drivers/iio/light/Kconfig"
+source "drivers/iio/magnetometer/Kconfig"
+source "drivers/iio/multiplexer/Kconfig"
+source "drivers/iio/orientation/Kconfig"
+source "drivers/iio/test/Kconfig"
+if IIO_TRIGGER
+   source "drivers/iio/trigger/Kconfig"
+endif #IIO_TRIGGER
+source "drivers/iio/position/Kconfig"
+source "drivers/iio/potentiometer/Kconfig"
+source "drivers/iio/potentiostat/Kconfig"
+source "drivers/iio/pressure/Kconfig"
+source "drivers/iio/proximity/Kconfig"
+source "drivers/iio/resolver/Kconfig"
+source "drivers/iio/temperature/Kconfig"
+
+endif # IIO