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, 41 insertions, 0 deletions

diff --git a/drivers/pci/endpoint/Kconfig b/drivers/pci/endpoint/Kconfig
new file mode 100644
index 000000000..8dad291be
--- /dev/null
+++ b/drivers/pci/endpoint/Kconfig
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# PCI Endpoint Support
+#
+
+menu "PCI Endpoint"
+
+config PCI_ENDPOINT
+	bool "PCI Endpoint Support"
+	depends on HAVE_PCI
+	help
+	   Enable this configuration option to support configurable PCI
+	   endpoint. This should be enabled if the platform has a PCI
+	   controller that can operate in endpoint mode.
+
+	   Enabling this option will build the endpoint library, which
+	   includes endpoint controller library and endpoint function
+	   library.
+
+	   If in doubt, say "N" to disable Endpoint support.
+
+config PCI_ENDPOINT_CONFIGFS
+	bool "PCI Endpoint Configfs Support"
+	depends on PCI_ENDPOINT
+	select CONFIGFS_FS
+	help
+	   This will enable the configfs entry that can be used to
+	   configure the endpoint function and used to bind the
+	   function with an endpoint controller.
+
+config PCI_ENDPOINT_MSI_DOORBELL
+	bool "PCI Endpoint MSI Doorbell Support"
+	depends on PCI_ENDPOINT && GENERIC_MSI_IRQ
+	help
+	  This enables the EP's MSI interrupt controller to function as a
+	  doorbell. The RC can trigger doorbell in EP by writing data to a
+	  dedicated BAR, which the EP maps to the controller's message address.
+
+source "drivers/pci/endpoint/functions/Kconfig"
+
+endmenu