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, 168 insertions, 0 deletions

diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
new file mode 100644
index 000000000..1cf1a9895
--- /dev/null
+++ b/drivers/ssb/Kconfig
@@ -0,0 +1,168 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SSB_POSSIBLE
+	bool
+	depends on HAS_IOMEM && HAS_DMA
+	default y
+
+menuconfig SSB
+	tristate "Sonics Silicon Backplane support"
+	depends on SSB_POSSIBLE
+	help
+	  Support for the Sonics Silicon Backplane bus.
+	  You only need to enable this option, if you are
+	  configuring a kernel for an embedded system with
+	  this bus.
+	  It will be auto-selected if needed in other
+	  environments.
+
+	  The module will be called ssb.
+
+	  If unsure, say N.
+
+if SSB
+
+# Common SPROM support routines
+config SSB_SPROM
+	bool
+
+# Support for Block-I/O. SELECT this from the driver that needs it.
+config SSB_BLOCKIO
+	bool
+	depends on SSB
+
+config SSB_PCIHOST_POSSIBLE
+	bool
+	depends on SSB && (PCI = y || PCI = SSB) && (PCI_DRIVERS_LEGACY || !MIPS)
+	default y
+
+config SSB_PCIHOST
+	bool "Support for SSB on PCI-bus host"
+	depends on SSB_PCIHOST_POSSIBLE
+	select SSB_SPROM
+	default y
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a PCI device.
+
+	  If unsure, say Y
+
+config SSB_B43_PCI_BRIDGE
+	bool
+	depends on SSB_PCIHOST
+	default n
+
+config SSB_PCMCIAHOST_POSSIBLE
+	bool
+	depends on SSB && (PCMCIA = y || PCMCIA = SSB)
+	default y
+
+config SSB_PCMCIAHOST
+	bool "Support for SSB on PCMCIA-bus host"
+	depends on SSB_PCMCIAHOST_POSSIBLE
+	select SSB_SPROM
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a PCMCIA device.
+
+	  If unsure, say N
+
+config SSB_SDIOHOST_POSSIBLE
+	bool
+	depends on SSB && (MMC = y || MMC = SSB)
+	default y
+
+config SSB_SDIOHOST
+	bool "Support for SSB on SDIO-bus host"
+	depends on SSB_SDIOHOST_POSSIBLE
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a SDIO device.
+
+	  If unsure, say N
+
+config SSB_HOST_SOC
+	bool "Support for SSB bus on SoC"
+	depends on SSB && BCM47XX_NVRAM
+	select SSB_SPROM
+	help
+	  Host interface for a SSB directly mapped into memory. This is
+	  for some Broadcom SoCs from the BCM47xx and BCM53xx lines.
+
+	  If unsure, say N
+
+config SSB_SERIAL
+	bool
+	depends on SSB
+	# ChipCommon and ExtIf serial support routines.
+
+config SSB_DRIVER_PCICORE_POSSIBLE
+	bool
+	depends on SSB_PCIHOST
+	default y
+
+config SSB_DRIVER_PCICORE
+	bool "SSB PCI core driver"
+	depends on SSB_DRIVER_PCICORE_POSSIBLE
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom PCI core.
+
+	  If unsure, say Y
+
+config SSB_PCICORE_HOSTMODE
+	bool "Hostmode support for SSB PCI core"
+	depends on SSB_DRIVER_PCICORE && SSB_DRIVER_MIPS && SSB = y
+	help
+	  PCIcore hostmode operation (external PCI bus).
+
+config SSB_DRIVER_MIPS
+	bool "SSB Broadcom MIPS core driver"
+	depends on SSB && MIPS
+	select SSB_SERIAL
+	select SSB_SFLASH
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom MIPS core.
+
+	  If unsure, say N
+
+config SSB_SFLASH
+	bool "SSB serial flash support"
+	depends on SSB_DRIVER_MIPS
+	default y
+
+# Assumption: We are on embedded, if we compile the MIPS core.
+config SSB_EMBEDDED
+	bool
+	depends on SSB_DRIVER_MIPS
+	depends on PCI=n || SSB_PCICORE_HOSTMODE
+	default y
+
+config SSB_DRIVER_EXTIF
+	bool "SSB Broadcom EXTIF core driver"
+	depends on SSB_DRIVER_MIPS
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom EXTIF core.
+
+	  If unsure, say N
+
+config SSB_DRIVER_GIGE
+	bool "SSB Broadcom Gigabit Ethernet driver"
+	depends on SSB_PCIHOST_POSSIBLE && SSB_EMBEDDED && MIPS
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom Gigabit Ethernet.
+
+	  If unsure, say N
+
+config SSB_DRIVER_GPIO
+	bool "SSB GPIO driver"
+	depends on SSB && GPIOLIB
+	select IRQ_DOMAIN if SSB_EMBEDDED
+	help
+	  Driver to provide access to the GPIO pins on the bus.
+
+	  If unsure, say N
+
+endif # SSB