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, 68 insertions, 0 deletions

diff --git a/drivers/usb/atm/Kconfig b/drivers/usb/atm/Kconfig
new file mode 100644
index 000000000..3d958a1a1
--- /dev/null
+++ b/drivers/usb/atm/Kconfig
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# USB/ATM DSL configuration
+#
+
+menuconfig USB_ATM
+	tristate "USB DSL modem support"
+	depends on ATM
+	select CRC32
+	help
+	  Say Y here if you want to connect a USB Digital Subscriber Line (DSL)
+	  modem to your computer's USB port.  You will then need to choose your
+	  modem from the list below.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usbatm.
+
+if USB_ATM
+
+config USB_SPEEDTOUCH
+	tristate "Speedtouch USB support"
+	select FW_LOADER
+	help
+	  Say Y here if you have an SpeedTouch USB or SpeedTouch 330
+	  modem.  In order to use your modem you will need to install the 
+	  two parts of the firmware, extracted by the user space tools; see
+	  <http://www.linux-usb.org/SpeedTouch/> for details.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called speedtch.
+
+config USB_CXACRU
+	tristate "Conexant AccessRunner USB support"
+	select FW_LOADER
+	help
+	  Say Y here if you have an ADSL USB modem based on the Conexant
+	  AccessRunner chipset.  In order to use your modem you will need to
+	  install the firmware, extracted by the user space tools; see
+	  <http://accessrunner.sourceforge.net/> for details.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cxacru.
+
+config USB_UEAGLEATM
+	tristate "ADI 930 and eagle USB DSL modem"
+	select FW_LOADER
+	help
+	  Say Y here if you have an ADSL USB modem based on the ADI 930
+	  or eagle chipset. In order to use your modem you will need to
+	  install firmwares and CMV (Command Management Variables); see
+	  <https://gna.org/projects/ueagleatm/> for details.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ueagle-atm.
+
+config USB_XUSBATM
+	tristate "Other USB DSL modem support"
+	help
+	  Say Y here if you have a DSL USB modem not explicitly supported by
+	  another USB DSL drivers.  In order to use your modem you will need to
+	  pass the vendor ID, product ID, and endpoint numbers for transmission
+	  and reception as module parameters.  You may need to initialize
+	  the modem using a user space utility (a firmware loader for example).
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called xusbatm.
+
+endif # USB_ATM