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, 139 insertions, 0 deletions

diff --git a/drivers/hid/hid-picolcd_cir.c b/drivers/hid/hid-picolcd_cir.c
new file mode 100644
index 000000000..6d4c636e1
--- /dev/null
+++ b/drivers/hid/hid-picolcd_cir.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/***************************************************************************
+ *   Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org>  *
+ *                                                                         *
+ *   Based on Logitech G13 driver (v0.4)                                   *
+ *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu>   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include <linux/hid.h>
+#include <linux/hid-debug.h>
+#include <linux/input.h>
+#include "hid-ids.h"
+
+#include <linux/fb.h>
+#include <linux/vmalloc.h>
+#include <linux/backlight.h>
+#include <linux/lcd.h>
+
+#include <linux/leds.h>
+
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+
+#include <linux/completion.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <media/rc-core.h>
+
+#include "hid-picolcd.h"
+
+
+int picolcd_raw_cir(struct picolcd_data *data,
+		struct hid_report *report, u8 *raw_data, int size)
+{
+	unsigned long flags;
+	int i, w, sz;
+	struct ir_raw_event rawir = {};
+
+	/* ignore if rc_dev is NULL or status is shunned */
+	spin_lock_irqsave(&data->lock, flags);
+	if (!data->rc_dev || (data->status & PICOLCD_CIR_SHUN)) {
+		spin_unlock_irqrestore(&data->lock, flags);
+		return 1;
+	}
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	/* PicoLCD USB packets contain 16-bit intervals in network order,
+	 * with value negated for pulse. Intervals are in microseconds.
+	 *
+	 * Note: some userspace LIRC code for PicoLCD says negated values
+	 * for space - is it a matter of IR chip? (pulse for my TSOP2236)
+	 *
+	 * In addition, the first interval seems to be around 15000 + base
+	 * interval for non-first report of IR data - thus the quirk below
+	 * to get RC_CODE to understand Sony and JVC remotes I have at hand
+	 */
+	sz = size > 0 ? min((int)raw_data[0], size-1) : 0;
+	for (i = 0; i+1 < sz; i += 2) {
+		w = (raw_data[i] << 8) | (raw_data[i+1]);
+		rawir.pulse = !!(w & 0x8000);
+		rawir.duration = rawir.pulse ? (65536 - w) : w;
+		/* Quirk!! - see above */
+		if (i == 0 && rawir.duration > 15000)
+			rawir.duration -= 15000;
+		ir_raw_event_store(data->rc_dev, &rawir);
+	}
+	ir_raw_event_handle(data->rc_dev);
+
+	return 1;
+}
+
+static int picolcd_cir_open(struct rc_dev *dev)
+{
+	struct picolcd_data *data = dev->priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->lock, flags);
+	data->status &= ~PICOLCD_CIR_SHUN;
+	spin_unlock_irqrestore(&data->lock, flags);
+	return 0;
+}
+
+static void picolcd_cir_close(struct rc_dev *dev)
+{
+	struct picolcd_data *data = dev->priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->lock, flags);
+	data->status |= PICOLCD_CIR_SHUN;
+	spin_unlock_irqrestore(&data->lock, flags);
+}
+
+/* initialize CIR input device */
+int picolcd_init_cir(struct picolcd_data *data, struct hid_report *report)
+{
+	struct rc_dev *rdev;
+	int ret = 0;
+
+	rdev = rc_allocate_device(RC_DRIVER_IR_RAW);
+	if (!rdev)
+		return -ENOMEM;
+
+	rdev->priv             = data;
+	rdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
+	rdev->open             = picolcd_cir_open;
+	rdev->close            = picolcd_cir_close;
+	rdev->device_name      = data->hdev->name;
+	rdev->input_phys       = data->hdev->phys;
+	rdev->input_id.bustype = data->hdev->bus;
+	rdev->input_id.vendor  = data->hdev->vendor;
+	rdev->input_id.product = data->hdev->product;
+	rdev->input_id.version = data->hdev->version;
+	rdev->dev.parent       = &data->hdev->dev;
+	rdev->driver_name      = PICOLCD_NAME;
+	rdev->map_name         = RC_MAP_RC6_MCE;
+	rdev->timeout          = MS_TO_US(100);
+	rdev->rx_resolution    = 1;
+
+	ret = rc_register_device(rdev);
+	if (ret)
+		goto err;
+	data->rc_dev = rdev;
+	return 0;
+
+err:
+	rc_free_device(rdev);
+	return ret;
+}
+
+void picolcd_exit_cir(struct picolcd_data *data)
+{
+	struct rc_dev *rdev = data->rc_dev;
+
+	data->rc_dev = NULL;
+	rc_unregister_device(rdev);
+	rc_free_device(rdev);
+}
+