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, 48 insertions, 0 deletions

diff --git a/drivers/pnp/Kconfig b/drivers/pnp/Kconfig
new file mode 100644
index 000000000..a72141dff
--- /dev/null
+++ b/drivers/pnp/Kconfig
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Plug and Play configuration
+#
+
+menuconfig PNP
+	bool "Plug and Play support"
+	depends on HAS_IOMEM
+	depends on ISA || ACPI
+	help
+	  Plug and Play (PnP) is a standard for peripherals which allows those
+	  peripherals to be configured by software, e.g. assign IRQ's or other
+	  parameters. No jumpers on the cards are needed, instead the values
+	  are provided to the cards from the BIOS, from the operating system,
+	  or using a user-space utility.
+
+	  Say Y here if you would like Linux to configure your Plug and Play
+	  devices. You should then also say Y to all of the protocols below.
+	  Alternatively, you can say N here and configure your PnP devices
+	  using user space utilities such as the isapnptools package.
+
+	  If unsure, say Y.
+
+config PNP_DEBUG_MESSAGES
+	default y
+	bool "PNP debugging messages"
+	depends on PNP
+	help
+	  Say Y here if you want the PNP layer to be able to produce debugging
+	  messages if needed.  The messages can be enabled at boot-time with
+	  the pnp.debug kernel parameter.
+
+	  This option allows you to save a bit of space if you do not want
+	  the messages to even be built into the kernel.
+
+	  If you have any doubts about this, say Y here.
+
+if PNP
+
+comment "Protocols"
+
+source "drivers/pnp/isapnp/Kconfig"
+
+source "drivers/pnp/pnpbios/Kconfig"
+
+source "drivers/pnp/pnpacpi/Kconfig"
+
+endif # PNP