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/include/soc/tegra/common.h b/include/soc/tegra/common.h
new file mode 100644
index 000000000..8ec1ac07f
--- /dev/null
+++ b/include/soc/tegra/common.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2014 NVIDIA Corporation
+ */
+
+#ifndef __SOC_TEGRA_COMMON_H__
+#define __SOC_TEGRA_COMMON_H__
+
+#include <linux/errno.h>
+#include <linux/types.h>
+
+struct device;
+
+/**
+ * Tegra SoC core device OPP table configuration
+ *
+ * @init_state: pre-initialize OPP state of a device
+ */
+struct tegra_core_opp_params {
+	bool init_state;
+};
+
+#ifdef CONFIG_ARCH_TEGRA
+bool soc_is_tegra(void);
+
+int devm_tegra_core_dev_init_opp_table(struct device *dev,
+				       struct tegra_core_opp_params *params);
+#else
+static inline bool soc_is_tegra(void)
+{
+	return false;
+}
+
+static inline int
+devm_tegra_core_dev_init_opp_table(struct device *dev,
+				   struct tegra_core_opp_params *params)
+{
+	return -ENODEV;
+}
+#endif
+
+static inline int
+devm_tegra_core_dev_init_opp_table_common(struct device *dev)
+{
+	struct tegra_core_opp_params opp_params = {};
+	int err;
+
+	opp_params.init_state = true;
+
+	err = devm_tegra_core_dev_init_opp_table(dev, &opp_params);
+	if (err != -ENODEV)
+		return err;
+
+	return 0;
+}
+
+#endif /* __SOC_TEGRA_COMMON_H__ */