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, 66 insertions, 0 deletions

diff --git a/drivers/hid/hid-monterey.c b/drivers/hid/hid-monterey.c
new file mode 100644
index 000000000..3089be990
--- /dev/null
+++ b/drivers/hid/hid-monterey.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for some monterey "special" devices
+ *
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2006-2007 Jiri Kosina
+ *  Copyright (c) 2008 Jiri Slaby
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+static const __u8 *mr_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize >= 31 && rdesc[29] == 0x05 && rdesc[30] == 0x09) {
+		hid_info(hdev, "fixing up button/consumer in HID report descriptor\n");
+		rdesc[30] = 0x0c;
+	}
+	return rdesc;
+}
+
+#define mr_map_key_clear(c)	hid_map_usage_clear(hi, usage, bit, max, \
+					EV_KEY, (c))
+static int mr_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_CONSUMER)
+		return 0;
+
+	switch (usage->hid & HID_USAGE) {
+	case 0x156: mr_map_key_clear(KEY_WORDPROCESSOR);	break;
+	case 0x157: mr_map_key_clear(KEY_SPREADSHEET);		break;
+	case 0x158: mr_map_key_clear(KEY_PRESENTATION);		break;
+	case 0x15c: mr_map_key_clear(KEY_STOP);			break;
+	default:
+		return 0;
+	}
+	return 1;
+}
+
+static const struct hid_device_id mr_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MONTEREY, USB_DEVICE_ID_GENIUS_KB29E) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, mr_devices);
+
+static struct hid_driver mr_driver = {
+	.name = "monterey",
+	.id_table = mr_devices,
+	.report_fixup = mr_report_fixup,
+	.input_mapping = mr_input_mapping,
+};
+module_hid_driver(mr_driver);
+
+MODULE_DESCRIPTION("HID driver for some monterey \"special\" devices");
+MODULE_LICENSE("GPL");