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, 56 insertions, 0 deletions

diff --git a/drivers/hwspinlock/Kconfig b/drivers/hwspinlock/Kconfig
new file mode 100644
index 000000000..d84e00084
--- /dev/null
+++ b/drivers/hwspinlock/Kconfig
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Generic HWSPINLOCK framework
+#
+
+menuconfig HWSPINLOCK
+	bool "Hardware Spinlock drivers"
+
+if HWSPINLOCK
+
+config HWSPINLOCK_OMAP
+	tristate "OMAP Hardware Spinlock device"
+	depends on ARCH_OMAP4 || SOC_OMAP5 || SOC_DRA7XX || SOC_AM33XX || SOC_AM43XX || ARCH_K3 || COMPILE_TEST
+	help
+	  Say y here to support the OMAP Hardware Spinlock device (firstly
+	  introduced in OMAP4).
+
+	  If unsure, say N.
+
+config HWSPINLOCK_QCOM
+	tristate "Qualcomm Hardware Spinlock device"
+	depends on ARCH_QCOM || COMPILE_TEST
+	select MFD_SYSCON
+	help
+	  Say y here to support the Qualcomm Hardware Mutex functionality, which
+	  provides a synchronisation mechanism for the various processors on
+	  the SoC.
+
+	  If unsure, say N.
+
+config HWSPINLOCK_SPRD
+	tristate "SPRD Hardware Spinlock device"
+	depends on ARCH_SPRD || COMPILE_TEST
+	help
+	  Say y here to support the SPRD Hardware Spinlock device.
+
+	  If unsure, say N.
+
+config HWSPINLOCK_STM32
+	tristate "STM32 Hardware Spinlock device"
+	depends on MACH_STM32MP157 || COMPILE_TEST
+	help
+	  Say y here to support the STM32 Hardware Spinlock device.
+
+	  If unsure, say N.
+
+config HWSPINLOCK_SUN6I
+	tristate "SUN6I Hardware Spinlock device"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	help
+	  Say y here to support the SUN6I Hardware Spinlock device which can be
+	  found in most of the sun6i compatible Allwinner SoCs.
+
+	  If unsure, say N.
+
+endif # HWSPINLOCK