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, 40 insertions, 0 deletions

diff --git a/drivers/hid/surface-hid/Kconfig b/drivers/hid/surface-hid/Kconfig
new file mode 100644
index 000000000..d0cfd0d29
--- /dev/null
+++ b/drivers/hid/surface-hid/Kconfig
@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: GPL-2.0+
+menu "Surface System Aggregator Module HID support"
+	depends on SURFACE_AGGREGATOR
+
+config SURFACE_HID
+	tristate "HID transport driver for Surface System Aggregator Module"
+	depends on SURFACE_AGGREGATOR_REGISTRY
+	select SURFACE_HID_CORE
+	help
+	  Driver to support integrated HID devices on newer Microsoft Surface
+	  models.
+
+	  This driver provides support for the HID transport protocol provided
+	  by the Surface Aggregator Module (i.e. the embedded controller) on
+	  7th-generation Microsoft Surface devices, i.e. Surface Book 3 and
+	  Surface Laptop 3. On those models, it is mainly used to connect the
+	  integrated touchpad and keyboard.
+
+	  Say M or Y here, if you want support for integrated HID devices, i.e.
+	  integrated touchpad and keyboard, on 7th generation Microsoft Surface
+	  models.
+
+config SURFACE_KBD
+	tristate "HID keyboard transport driver for Surface System Aggregator Module"
+	select SURFACE_HID_CORE
+	help
+	  Driver to support HID keyboards on Surface Laptop 1 and 2 devices.
+
+	  This driver provides support for the HID transport protocol provided
+	  by the Surface Aggregator Module (i.e. the embedded controller) on
+	  Microsoft Surface Laptops 1 and 2. It is used to connect the
+	  integrated keyboard on those devices.
+
+	  Say M or Y here, if you want support for the integrated keyboard on
+	  Microsoft Surface Laptops 1 and 2.
+
+endmenu
+
+config SURFACE_HID_CORE
+	tristate