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, 57 insertions, 0 deletions

diff --git a/rust/helpers/regulator.c b/rust/helpers/regulator.c
new file mode 100644
index 000000000..9ec5237f4
--- /dev/null
+++ b/rust/helpers/regulator.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/regulator/consumer.h>
+
+#ifndef CONFIG_REGULATOR
+
+__rust_helper void rust_helper_regulator_put(struct regulator *regulator)
+{
+	regulator_put(regulator);
+}
+
+__rust_helper int rust_helper_regulator_set_voltage(struct regulator *regulator,
+						    int min_uV, int max_uV)
+{
+	return regulator_set_voltage(regulator, min_uV, max_uV);
+}
+
+__rust_helper int rust_helper_regulator_get_voltage(struct regulator *regulator)
+{
+	return regulator_get_voltage(regulator);
+}
+
+__rust_helper struct regulator *rust_helper_regulator_get(struct device *dev,
+							  const char *id)
+{
+	return regulator_get(dev, id);
+}
+
+__rust_helper int rust_helper_regulator_enable(struct regulator *regulator)
+{
+	return regulator_enable(regulator);
+}
+
+__rust_helper int rust_helper_regulator_disable(struct regulator *regulator)
+{
+	return regulator_disable(regulator);
+}
+
+__rust_helper int rust_helper_regulator_is_enabled(struct regulator *regulator)
+{
+	return regulator_is_enabled(regulator);
+}
+
+__rust_helper int rust_helper_devm_regulator_get_enable(struct device *dev,
+							const char *id)
+{
+	return devm_regulator_get_enable(dev, id);
+}
+
+__rust_helper int
+rust_helper_devm_regulator_get_enable_optional(struct device *dev,
+					       const char *id)
+{
+	return devm_regulator_get_enable_optional(dev, id);
+}
+
+#endif