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, 44 insertions, 0 deletions

diff --git a/drivers/sh/intc/Kconfig b/drivers/sh/intc/Kconfig
new file mode 100644
index 000000000..5c701709f
--- /dev/null
+++ b/drivers/sh/intc/Kconfig
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SH_INTC
+	bool
+	select IRQ_DOMAIN
+
+if SH_INTC
+
+comment "Interrupt controller options"
+
+config INTC_USERIMASK
+	bool "Userspace interrupt masking support"
+	depends on (SUPERH && CPU_SH4A) || COMPILE_TEST
+	help
+	  This enables support for hardware-assisted userspace hardirq
+	  masking.
+
+	  SH-4A and newer interrupt blocks all support a special shadowed
+	  page with all non-masking registers obscured when mapped in to
+	  userspace. This is primarily for use by userspace device
+	  drivers that are using special priority levels.
+
+	  If in doubt, say N.
+
+config INTC_BALANCING
+	bool "Hardware IRQ balancing support"
+	depends on SMP && SUPERH && CPU_SHX3
+	help
+	  This enables support for IRQ auto-distribution mode on SH-X3
+	  SMP parts. All of the balancing and CPU wakeup decisions are
+	  taken care of automatically by hardware for distributed
+	  vectors.
+
+	  If in doubt, say N.
+
+config INTC_MAPPING_DEBUG
+	bool "Expose IRQ to per-controller id mapping via debugfs"
+	depends on DEBUG_FS
+	help
+	  This will create a debugfs entry for showing the relationship
+	  between system IRQs and the per-controller id tables.
+
+	  If in doubt, say N.
+
+endif