From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- drivers/input/serio/rpckbd.c | 152 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 drivers/input/serio/rpckbd.c (limited to 'drivers/input/serio/rpckbd.c') diff --git a/drivers/input/serio/rpckbd.c b/drivers/input/serio/rpckbd.c new file mode 100644 index 000000000..4d817850b --- /dev/null +++ b/drivers/input/serio/rpckbd.c @@ -0,0 +1,152 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2000-2001 Vojtech Pavlik + * Copyright (c) 2002 Russell King + */ + +/* + * Acorn RiscPC PS/2 keyboard controller driver for Linux/ARM + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +MODULE_AUTHOR("Vojtech Pavlik, Russell King"); +MODULE_DESCRIPTION("Acorn RiscPC PS/2 keyboard controller driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:kart"); + +struct rpckbd_data { + int tx_irq; + int rx_irq; +}; + +static int rpckbd_write(struct serio *port, unsigned char val) +{ + while (!(iomd_readb(IOMD_KCTRL) & (1 << 7))) + cpu_relax(); + + iomd_writeb(val, IOMD_KARTTX); + + return 0; +} + +static irqreturn_t rpckbd_rx(int irq, void *dev_id) +{ + struct serio *port = dev_id; + unsigned int byte; + int handled = IRQ_NONE; + + while (iomd_readb(IOMD_KCTRL) & (1 << 5)) { + byte = iomd_readb(IOMD_KARTRX); + + serio_interrupt(port, byte, 0); + handled = IRQ_HANDLED; + } + return handled; +} + +static irqreturn_t rpckbd_tx(int irq, void *dev_id) +{ + return IRQ_HANDLED; +} + +static int rpckbd_open(struct serio *port) +{ + struct rpckbd_data *rpckbd = port->port_data; + + /* Reset the keyboard state machine. */ + iomd_writeb(0, IOMD_KCTRL); + iomd_writeb(8, IOMD_KCTRL); + iomd_readb(IOMD_KARTRX); + + if (request_irq(rpckbd->rx_irq, rpckbd_rx, 0, "rpckbd", port) != 0) { + printk(KERN_ERR "rpckbd.c: Could not allocate keyboard receive IRQ\n"); + return -EBUSY; + } + + if (request_irq(rpckbd->tx_irq, rpckbd_tx, 0, "rpckbd", port) != 0) { + printk(KERN_ERR "rpckbd.c: Could not allocate keyboard transmit IRQ\n"); + free_irq(rpckbd->rx_irq, port); + return -EBUSY; + } + + return 0; +} + +static void rpckbd_close(struct serio *port) +{ + struct rpckbd_data *rpckbd = port->port_data; + + free_irq(rpckbd->rx_irq, port); + free_irq(rpckbd->tx_irq, port); +} + +/* + * Allocate and initialize serio structure for subsequent registration + * with serio core. + */ +static int rpckbd_probe(struct platform_device *dev) +{ + struct rpckbd_data *rpckbd; + struct serio *serio; + int tx_irq, rx_irq; + + rx_irq = platform_get_irq(dev, 0); + if (rx_irq < 0) + return rx_irq; + + tx_irq = platform_get_irq(dev, 1); + if (tx_irq < 0) + return tx_irq; + + serio = kzalloc_obj(*serio); + rpckbd = kzalloc_obj(*rpckbd); + if (!serio || !rpckbd) { + kfree(rpckbd); + kfree(serio); + return -ENOMEM; + } + + rpckbd->rx_irq = rx_irq; + rpckbd->tx_irq = tx_irq; + + serio->id.type = SERIO_8042; + serio->write = rpckbd_write; + serio->open = rpckbd_open; + serio->close = rpckbd_close; + serio->dev.parent = &dev->dev; + serio->port_data = rpckbd; + strscpy(serio->name, "RiscPC PS/2 kbd port", sizeof(serio->name)); + strscpy(serio->phys, "rpckbd/serio0", sizeof(serio->phys)); + + platform_set_drvdata(dev, serio); + serio_register_port(serio); + return 0; +} + +static void rpckbd_remove(struct platform_device *dev) +{ + struct serio *serio = platform_get_drvdata(dev); + struct rpckbd_data *rpckbd = serio->port_data; + + serio_unregister_port(serio); + kfree(rpckbd); +} + +static struct platform_driver rpckbd_driver = { + .probe = rpckbd_probe, + .remove = rpckbd_remove, + .driver = { + .name = "kart", + }, +}; +module_platform_driver(rpckbd_driver); -- cgit v1.3.1