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, 83 insertions, 0 deletions

diff --git a/drivers/net/pse-pd/Kconfig b/drivers/net/pse-pd/Kconfig
new file mode 100644
index 000000000..a0f2ae668
--- /dev/null
+++ b/drivers/net/pse-pd/Kconfig
@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Ethernet Power Sourcing Equipment drivers
+#
+
+menuconfig PSE_CONTROLLER
+	bool "Ethernet Power Sourcing Equipment Support"
+	depends on REGULATOR
+	help
+	  Generic Power Sourcing Equipment Controller support.
+
+	  If unsure, say no.
+
+if PSE_CONTROLLER
+
+config PSE_REALTEK_MCU
+	tristate
+	help
+	  Shared core for the Realtek PSE MCU driver. This is selected
+	  automatically by the transport options below.
+
+config PSE_REALTEK_MCU_I2C
+	tristate "Realtek PSE MCU driver (I2C transport)"
+	depends on I2C
+	select PSE_REALTEK_MCU
+	help
+	  Driver for the microcontroller (MCU) that fronts the PSE
+	  hardware on various Realtek-based managed switches, attached
+	  via I2C/SMBus. The MCU exposes a message-based protocol; the actual
+	  PSE silicon is not accessed directly. To compile this driver as a
+	  module, choose M here: the module will be called realtek-pse-mcu-i2c.
+
+config PSE_REALTEK_MCU_UART
+	tristate "Realtek PSE MCU driver (UART transport)"
+	depends on SERIAL_DEV_BUS
+	select PSE_REALTEK_MCU
+	help
+	  Driver for the microcontroller (MCU) that fronts the PSE
+	  hardware on various Realtek-based managed switches, attached
+	  via UART. The MCU exposes a message-based protocol; the actual PSE
+	  silicon is not accessed directly. To compile this driver as a
+	  module, choose M here: the module will be called realtek-pse-mcu-uart.
+
+config PSE_REGULATOR
+	tristate "Regulator based PSE controller"
+	help
+	  This module provides support for simple regulator based Ethernet Power
+	  Sourcing Equipment without automatic classification support. For
+	  example for basic implementation of PoDL (802.3bu) specification.
+
+config PSE_PD692X0
+	tristate "PD692X0 PSE controller"
+	depends on I2C
+	select FW_LOADER
+	select FW_UPLOAD
+	help
+	  This module provides support for PD692x0 regulator based Ethernet
+	  Power Sourcing Equipment.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pd692x0.
+
+config PSE_SI3474
+	tristate "Si3474 PSE controller"
+	depends on I2C
+	help
+	  This module provides support for Si3474 regulator based Ethernet
+	  Power Sourcing Equipment.
+	  Only 4-pair PSE configurations are supported.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called si3474.
+
+config PSE_TPS23881
+	tristate "TPS23881 PSE controller"
+	depends on I2C
+	help
+	  This module provides support for TPS23881 regulator based Ethernet
+	  Power Sourcing Equipment.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called tps23881.
+endif