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, 268 insertions, 0 deletions

diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
new file mode 100644
index 000000000..6abc9302c
--- /dev/null
+++ b/drivers/media/Kconfig
@@ -0,0 +1,268 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Multimedia device configuration
+#
+
+#
+# NOTE: CEC and Remote Controller support should not depend on MEDIA_SUPPORT
+#
+source "drivers/media/rc/Kconfig"
+source "drivers/media/cec/Kconfig"
+
+menuconfig MEDIA_SUPPORT
+	tristate "Multimedia support"
+	depends on HAS_IOMEM
+	help
+	  If you want to use media devices, including Webcams, Video grabber
+	  devices and/or TV devices, V4L2 codecs, etc, enable this option
+	  and other options below.
+
+	  Additional info and docs are available on the web at
+	  <https://linuxtv.org>
+
+if MEDIA_SUPPORT
+
+config MEDIA_SUPPORT_FILTER
+	bool "Filter media drivers"
+	default y if !EXPERT
+	help
+	   Configuring the media subsystem can be complex, as there are
+	   hundreds of drivers and other config options.
+
+	   This menu offers option that will help the Kernel's config
+	   system to hide drivers that are out of the scope of the
+	   user needs, and disabling core support for unused APIs.
+
+	   If not selected, all non-optional media core functionality
+	   needed to support media drivers will be enabled. Also, all
+	   media device drivers should be shown.
+
+config MEDIA_SUBDRV_AUTOSELECT
+	bool "Autoselect ancillary drivers (tuners, sensors, i2c, spi, frontends)"
+	depends on HAS_IOMEM
+	select I2C
+	select I2C_MUX
+	default y if MEDIA_SUPPORT_FILTER
+	help
+	  By default, a media driver auto-selects all possible ancillary
+	  devices such as tuners, sensors, video encoders/decoders and
+	  frontends, that are used by any of the supported devices.
+
+	  This is generally the right thing to do, except when there
+	  are strict constraints with regards to the kernel size,
+	  like on embedded systems.
+
+	  Use this option with care, as deselecting ancillary drivers which
+	  are, in fact, necessary will result in the lack of the needed
+	  functionality for your device (it may not tune or may not have
+	  the needed demodulators).
+
+	  If unsure say Y.
+
+menu "Media device types"
+
+#
+# Multimedia support - automatically enable V4L2 and DVB core
+#
+config MEDIA_CAMERA_SUPPORT
+	bool
+	prompt "Cameras and video grabbers" if MEDIA_SUPPORT_FILTER
+	default y if !MEDIA_SUPPORT_FILTER
+	help
+	  Enable support for webcams and video grabbers.
+
+	  Say Y when you have a webcam or a video capture grabber board.
+
+config MEDIA_ANALOG_TV_SUPPORT
+	bool
+	prompt "Analog TV" if MEDIA_SUPPORT_FILTER
+	default y if !MEDIA_SUPPORT_FILTER
+	help
+	  Enable analog TV support.
+
+	  Say Y when you have a TV board with analog support or with a
+	  hybrid analog/digital TV chipset.
+
+	  Note: There are several DVB cards that are based on chips that
+		support both analog and digital TV. Disabling this option
+		will disable support for them.
+
+config MEDIA_DIGITAL_TV_SUPPORT
+	bool
+	prompt "Digital TV" if MEDIA_SUPPORT_FILTER
+	default y if !MEDIA_SUPPORT_FILTER
+	help
+	  Enable digital TV support.
+
+	  Say Y when you have a board with digital support or a board with
+	  hybrid digital TV and analog TV.
+
+config MEDIA_RADIO_SUPPORT
+	bool
+	prompt "AM/FM radio receivers/transmitters" if MEDIA_SUPPORT_FILTER
+	default y if !MEDIA_SUPPORT_FILTER
+	help
+	  Enable AM/FM radio support.
+
+	  Additional info and docs are available on the web at
+	  <https://linuxtv.org>
+
+	  Say Y when you have a board with radio support.
+
+	  Note: There are several TV cards that are based on chips that
+		support radio reception. Disabling this option will
+		disable support for them.
+
+config MEDIA_SDR_SUPPORT
+	bool
+	prompt "Software defined radio" if MEDIA_SUPPORT_FILTER
+	default y if !MEDIA_SUPPORT_FILTER
+	help
+	  Enable software defined radio support.
+
+	  Say Y when you have a software defined radio device.
+
+config MEDIA_PLATFORM_SUPPORT
+	bool
+	prompt "Platform-specific devices" if MEDIA_SUPPORT_FILTER
+	default y if !MEDIA_SUPPORT_FILTER
+	help
+	  Enable support for complex cameras, codecs, and other hardware
+	  that are integrated at the CPU, GPU or on Image Signalling Processor
+	  and don't use PCI, USB or Firewire buses.
+
+	  This is found on Embedded hardware (SoC), on V4L2 codecs and
+	  on some GPU and newer CPU chipsets.
+
+	  Say Y when you want to be able to see such devices.
+
+config MEDIA_TEST_SUPPORT
+	bool
+	prompt "Test drivers" if MEDIA_SUPPORT_FILTER
+	default y if !MEDIA_SUPPORT_FILTER
+	help
+	  These drivers should not be used on production kernels, but
+	  can be useful on debug ones. This option enables several dummy drivers
+	  that simulate real hardware. Very useful to test userspace
+	  applications and to validate if the subsystem core doesn't
+	  have regressions.
+
+	  Say Y if you want to use some virtual test driver.
+
+	  In case of doubts, say N.
+	  Say Y when you have a software defined radio device.
+endmenu # media device types
+
+
+menu "Media core support"
+	visible if !MEDIA_SUPPORT_FILTER
+
+config VIDEO_DEV
+	tristate "Video4Linux core"
+	default MEDIA_CAMERA_SUPPORT || MEDIA_ANALOG_TV_SUPPORT || MEDIA_RADIO_SUPPORT || MEDIA_SDR_SUPPORT || MEDIA_PLATFORM_SUPPORT || MEDIA_TEST_SUPPORT
+	depends on (I2C || I2C=n)
+	select RATIONAL
+	select VIDEOBUF2_V4L2 if VIDEOBUF2_CORE
+	help
+	  Enables the V4L2 API, used by cameras, analog TV, video grabbers,
+	  radio devices and by some input devices.
+
+config MEDIA_CONTROLLER
+	bool "Media Controller API"
+	default MEDIA_CAMERA_SUPPORT || MEDIA_ANALOG_TV_SUPPORT || MEDIA_DIGITAL_TV_SUPPORT || MEDIA_PLATFORM_SUPPORT
+	help
+	  Enable the media controller API used to query media devices internal
+	  topology and configure it dynamically.
+
+	  This API is mostly used by camera interfaces in embedded platforms.
+
+#
+# DVB Core
+#	Only enables if one of DTV is selected
+#
+
+config DVB_CORE
+	tristate "DVB Core"
+	depends on MEDIA_DIGITAL_TV_SUPPORT
+	depends on (I2C || I2C=n)
+	default MEDIA_DIGITAL_TV_SUPPORT
+	select CRC32
+	help
+	  Enables the DVB API, used by Digital TV devices. Supports several
+	  standards, including DVB, ATSC, ISDB and CMDB.
+
+endmenu # Media core support
+
+#
+# Extra per-media API core functionality
+
+menu "Video4Linux options"
+	visible if VIDEO_DEV
+
+source "drivers/media/v4l2-core/Kconfig"
+endmenu
+
+menu "Media controller options"
+	visible if MEDIA_CONTROLLER
+
+source "drivers/media/mc/Kconfig"
+endmenu
+
+menu "Digital TV options"
+	visible if DVB_CORE
+
+source "drivers/media/dvb-core/Kconfig"
+endmenu
+
+menu "Media drivers"
+
+comment "Drivers filtered as selected at 'Filter media drivers'"
+	depends on MEDIA_SUPPORT_FILTER
+
+comment "Media drivers"
+
+source "drivers/media/usb/Kconfig"
+source "drivers/media/pci/Kconfig"
+source "drivers/media/radio/Kconfig"
+
+if MEDIA_PLATFORM_SUPPORT
+source "drivers/media/platform/Kconfig"
+source "drivers/media/mmc/Kconfig"
+endif
+
+if MEDIA_TEST_SUPPORT
+source "drivers/media/test-drivers/Kconfig"
+endif
+
+source "drivers/media/firewire/Kconfig"
+
+# Common driver options
+source "drivers/media/common/Kconfig"
+
+endmenu
+
+#
+# Ancillary drivers (tuners, i2c, spi, frontends)
+#
+
+config MEDIA_HIDE_ANCILLARY_SUBDRV
+	bool
+	depends on MEDIA_SUBDRV_AUTOSELECT && !COMPILE_TEST && !EXPERT
+	default y
+
+menu "Media ancillary drivers"
+
+config MEDIA_ATTACH
+	bool
+	depends on MEDIA_ANALOG_TV_SUPPORT || MEDIA_DIGITAL_TV_SUPPORT || MEDIA_RADIO_SUPPORT
+	depends on MODULES
+	default MODULES
+
+source "drivers/media/i2c/Kconfig"
+source "drivers/media/spi/Kconfig"
+source "drivers/media/tuners/Kconfig"
+source "drivers/media/dvb-frontends/Kconfig"
+
+endmenu
+
+endif # MEDIA_SUPPORT