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, 29 insertions, 0 deletions

diff --git a/drivers/usb/image/Kconfig b/drivers/usb/image/Kconfig
new file mode 100644
index 000000000..a65c638e7
--- /dev/null
+++ b/drivers/usb/image/Kconfig
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# USB Imaging devices configuration
+#
+comment "USB Imaging devices"
+
+config USB_MDC800
+	tristate "USB Mustek MDC800 Digital Camera support"
+	help
+	  Say Y here if you want to connect this type of still camera to
+	  your computer's USB port. This driver can be used with gphoto 0.4.3
+	  and higher (look at <http://www.gphoto.org/>).
+	  To use it create a device node with "mknod /dev/mustek c 180 32" and
+	  configure it in your software.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mdc800.
+
+config USB_MICROTEK
+	tristate "Microtek X6USB scanner support"
+	depends on SCSI
+	help
+	  Say Y here if you want support for the Microtek X6USB and
+	  possibly the Phantom 336CX, Phantom C6 and ScanMaker V6U(S)L.
+	  Support for anything but the X6 is experimental.
+	  Please report failures and successes.
+	  The scanner will appear as a scsi generic device to the rest
+	  of the system. Scsi support is required.
+	  This driver can be compiled as a module, called microtek.