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, 35 insertions, 0 deletions

diff --git a/drivers/misc/amd-sbi/Kconfig b/drivers/misc/amd-sbi/Kconfig
new file mode 100644
index 000000000..1a96b71f8
--- /dev/null
+++ b/drivers/misc/amd-sbi/Kconfig
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config AMD_SBRMI_I2C
+	tristate "AMD side band RMI support"
+	depends on I3C_OR_I2C
+	depends on ARM || ARM64 || COMPILE_TEST
+	select REGMAP_I2C
+	select REGMAP_I3C if I3C
+	help
+	  Side band RMI over I2C/I3C support for AMD out of band management.
+	  This driver is intended to run on the BMC, not the managed node.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called sbrmi-i2c.
+
+config AMD_SBRMI_HWMON
+	bool "SBRMI hardware monitoring"
+	depends on AMD_SBRMI_I2C && HWMON
+	depends on !(AMD_SBRMI_I2C=y && HWMON=m)
+	help
+	  This provides support for RMI device hardware monitoring. If enabled,
+	  a hardware monitoring device will be created for each socket in
+	  the system.
+
+config AMD_SBTSI
+	tristate "AMD side band TSI support"
+	depends on I3C_OR_I2C
+	depends on ARM || ARM64 || COMPILE_TEST
+	select AUXILIARY_BUS
+	help
+	  Enables support for the AMD SB-TSI (Side Band Temperature Sensor
+	  Interface) driver, which provides access to emulated CPU temperature
+	  sensors on AMD SoCs via an I2C/I3C connected BMC device.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called sbtsi.