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, 43 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/xilinx.txt b/Documentation/devicetree/bindings/xilinx.txt
new file mode 100644
index 000000000..a1a2cde7b
--- /dev/null
+++ b/Documentation/devicetree/bindings/xilinx.txt
@@ -0,0 +1,43 @@
+   Bindings for specific devices:
+
+      i) Xilinx ML300 Framebuffer
+
+      Simple framebuffer device from the ML300 reference design (also on the
+      ML403 reference design as well as others).
+
+      Optional properties:
+       - resolution = <xres yres> : pixel resolution of framebuffer.  Some
+                                    implementations use a different resolution.
+                                    Default is <d#640 d#480>
+       - virt-resolution = <xvirt yvirt> : Size of framebuffer in memory.
+                                           Default is <d#1024 d#480>.
+       - rotate-display (empty) : rotate display 180 degrees.
+
+      v) Xilinx hwicap
+
+		Xilinx hwicap devices provide access to the configuration logic
+		of the FPGA through the Internal Configuration Access Port
+		(ICAP).  The ICAP enables partial reconfiguration of the FPGA,
+		readback of the configuration information, and some control over
+		'warm boots' of the FPGA fabric.
+
+		Required properties:
+		- xlnx,family : The family of the FPGA, necessary since the
+                      capabilities of the underlying ICAP hardware
+                      differ between different families.  May be
+                      'virtex2p', 'virtex4', or 'virtex5'.
+		- compatible : should contain "xlnx,xps-hwicap-1.00.a" or
+				"xlnx,opb-hwicap-1.00.b".
+
+      vii) Xilinx USB Host controller
+
+      The Xilinx USB host controller is EHCI compatible but with a different
+      base address for the EHCI registers, and it is always a big-endian
+      USB Host controller. The hardware can be configured as high speed only,
+      or high speed/full speed hybrid.
+
+      Required properties:
+      - xlnx,support-usb-fs: A value 0 means the core is built as high speed
+                             only. A value 1 means the core also supports
+                             full speed devices.
+