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, 37 insertions, 0 deletions

diff --git a/drivers/pmdomain/arm/Kconfig b/drivers/pmdomain/arm/Kconfig
new file mode 100644
index 000000000..ba0b190a6
--- /dev/null
+++ b/drivers/pmdomain/arm/Kconfig
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ARM_SCMI_PERF_DOMAIN
+	tristate "SCMI performance domain driver"
+	depends on ARM_SCMI_PROTOCOL || (COMPILE_TEST && OF)
+	default ARM_SCMI_PROTOCOL
+	select PM_GENERIC_DOMAINS if PM
+	help
+	  This enables support for the SCMI performance domains which can be
+	  enabled or disabled via the SCP firmware.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called scmi_perf_domain.
+
+config ARM_SCMI_POWER_DOMAIN
+	tristate "SCMI power domain driver"
+	depends on ARM_SCMI_PROTOCOL || (COMPILE_TEST && OF)
+	default ARM_SCMI_PROTOCOL
+	select PM_GENERIC_DOMAINS if PM
+	help
+	  This enables support for the SCMI power domains which can be
+	  enabled or disabled via the SCP firmware
+
+	  This driver can also be built as a module. If so, the module
+	  will be called scmi_pm_domain. Note this may be needed early in boot
+	  before rootfs may be available.
+
+config ARM_SCPI_POWER_DOMAIN
+	tristate "SCPI power domain driver"
+	depends on ARM_SCPI_PROTOCOL || (COMPILE_TEST && OF)
+	default ARM_SCPI_PROTOCOL
+	select PM_GENERIC_DOMAINS if PM
+	help
+	  This enables support for the SCPI power domains which can be
+	  enabled or disabled via the SCP firmware
+
+	  This driver can also be built as a module. If so, the module will be
+	  called scpi_pm_domain.