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, 74 insertions, 0 deletions

diff --git a/drivers/scsi/arm/Kconfig b/drivers/scsi/arm/Kconfig
new file mode 100644
index 000000000..9f64133f9
--- /dev/null
+++ b/drivers/scsi/arm/Kconfig
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# SCSI driver configuration for Acorn
+#
+config SCSI_ACORNSCSI_3
+	tristate "Acorn SCSI card (aka30) support"
+	depends on ARCH_ACORN && SCSI
+	select SCSI_SPI_ATTRS
+	help
+	  This enables support for the Acorn SCSI card (aka30). If you have an
+	  Acorn system with one of these, say Y. If unsure, say N.
+
+config SCSI_ACORNSCSI_SYNC
+	bool "Support SCSI 2 Synchronous Transfers"
+	depends on SCSI_ACORNSCSI_3
+	help
+	  Say Y here to enable synchronous transfer negotiation with all
+	  targets on the Acorn SCSI card.
+
+	  In general, this improves performance; however some SCSI devices
+	  don't implement it properly, so the safe answer is N.
+
+config SCSI_ARXESCSI
+	tristate "ARXE SCSI support"
+	depends on ARCH_ACORN && SCSI
+	help
+	  Around 1991, Arxe Systems Limited released a high density floppy
+	  disc interface for the Acorn Archimedes range, to allow the use of
+	  HD discs from the then new A5000 on earlier models. This interface
+	  was either sold on its own or with an integral SCSI controller.
+	  Technical details on this NCR53c94-based device are available at
+	  <http://www.cryton.demon.co.uk/acornbits/scsi_arxe.html>
+	  Say Y here to compile in support for the SCSI controller.
+
+config SCSI_CUMANA_2
+	tristate "CumanaSCSI II support"
+	depends on ARCH_ACORN && SCSI
+	help
+	  This enables support for the Cumana SCSI II card. If you have an
+	  Acorn system with one of these, say Y. If unsure, say N.
+
+config SCSI_EESOXSCSI
+	tristate "EESOX support"
+	depends on ARCH_ACORN && SCSI
+	help
+	  This enables support for the EESOX SCSI card. If you have an Acorn
+	  system with one of these, say Y, otherwise say N.
+
+config SCSI_POWERTECSCSI
+	tristate "PowerTec support"
+	depends on ARCH_ACORN && SCSI
+	help
+	  This enables support for the Powertec SCSI card on Acorn systems. If
+	  you have one of these, say Y. If unsure, say N.
+
+comment "The following drivers are not fully supported"
+	depends on ARCH_ACORN
+
+config SCSI_CUMANA_1
+	tristate "CumanaSCSI I support"
+	depends on ARCH_ACORN && SCSI
+	select SCSI_SPI_ATTRS
+	help
+	  This enables support for the Cumana SCSI I card. If you have an
+	  Acorn system with one of these, say Y. If unsure, say N.
+
+config SCSI_OAK1
+	tristate "Oak SCSI support"
+	depends on ARCH_ACORN && SCSI
+	select SCSI_SPI_ATTRS
+	help
+	  This enables support for the Oak SCSI card. If you have an Acorn
+	  system with one of these, say Y. If unsure, say N.
+