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, 68 insertions, 0 deletions

diff --git a/rust/helpers/clk.c b/rust/helpers/clk.c
new file mode 100644
index 000000000..15fd7e469
--- /dev/null
+++ b/rust/helpers/clk.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/clk.h>
+
+/*
+ * The "inline" implementation of below helpers are only available when
+ * CONFIG_HAVE_CLK or CONFIG_HAVE_CLK_PREPARE aren't set.
+ */
+#ifndef CONFIG_HAVE_CLK
+__rust_helper struct clk *rust_helper_clk_get(struct device *dev,
+					      const char *id)
+{
+	return clk_get(dev, id);
+}
+
+__rust_helper void rust_helper_clk_put(struct clk *clk)
+{
+	clk_put(clk);
+}
+
+__rust_helper int rust_helper_clk_enable(struct clk *clk)
+{
+	return clk_enable(clk);
+}
+
+__rust_helper void rust_helper_clk_disable(struct clk *clk)
+{
+	clk_disable(clk);
+}
+
+__rust_helper unsigned long rust_helper_clk_get_rate(struct clk *clk)
+{
+	return clk_get_rate(clk);
+}
+
+__rust_helper int rust_helper_clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	return clk_set_rate(clk, rate);
+}
+#endif
+
+#ifndef CONFIG_HAVE_CLK_PREPARE
+__rust_helper int rust_helper_clk_prepare(struct clk *clk)
+{
+	return clk_prepare(clk);
+}
+
+__rust_helper void rust_helper_clk_unprepare(struct clk *clk)
+{
+	clk_unprepare(clk);
+}
+#endif
+
+__rust_helper struct clk *rust_helper_clk_get_optional(struct device *dev,
+						       const char *id)
+{
+	return clk_get_optional(dev, id);
+}
+
+__rust_helper int rust_helper_clk_prepare_enable(struct clk *clk)
+{
+	return clk_prepare_enable(clk);
+}
+
+__rust_helper void rust_helper_clk_disable_unprepare(struct clk *clk)
+{
+	clk_disable_unprepare(clk);
+}