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, 43 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/sp2.h b/drivers/media/dvb-frontends/sp2.h
new file mode 100644
index 000000000..b5ace0d76
--- /dev/null
+++ b/drivers/media/dvb-frontends/sp2.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * CIMaX SP2/HF CI driver
+ *
+ * Copyright (C) 2014 Olli Salonen <olli.salonen@iki.fi>
+ */
+
+#ifndef SP2_H
+#define SP2_H
+
+#include <media/dvb_ca_en50221.h>
+
+/*
+ * I2C address
+ * 0x40 (port 0)
+ * 0x41 (port 1)
+ */
+struct sp2_config {
+	/* dvb_adapter to attach the ci to */
+	struct dvb_adapter *dvb_adap;
+
+	/* function ci_control handles the device specific ci ops */
+	void *ci_control;
+
+	/* priv is passed back to function ci_control */
+	void *priv;
+};
+
+extern int sp2_ci_read_attribute_mem(struct dvb_ca_en50221 *en50221,
+					int slot, int addr);
+extern int sp2_ci_write_attribute_mem(struct dvb_ca_en50221 *en50221,
+					int slot, int addr, u8 data);
+extern int sp2_ci_read_cam_control(struct dvb_ca_en50221 *en50221,
+					int slot, u8 addr);
+extern int sp2_ci_write_cam_control(struct dvb_ca_en50221 *en50221,
+					int slot, u8 addr, u8 data);
+extern int sp2_ci_slot_reset(struct dvb_ca_en50221 *en50221, int slot);
+extern int sp2_ci_slot_shutdown(struct dvb_ca_en50221 *en50221, int slot);
+extern int sp2_ci_slot_ts_enable(struct dvb_ca_en50221 *en50221, int slot);
+extern int sp2_ci_poll_slot_status(struct dvb_ca_en50221 *en50221,
+					int slot, int open);
+
+#endif