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/q40kbd.c | 166 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 drivers/input/serio/q40kbd.c (limited to 'drivers/input/serio/q40kbd.c') diff --git a/drivers/input/serio/q40kbd.c b/drivers/input/serio/q40kbd.c new file mode 100644 index 000000000..2f553efbe --- /dev/null +++ b/drivers/input/serio/q40kbd.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2000-2001 Vojtech Pavlik + * + * Based on the work of: + * Richard Zidlicky + */ + +/* + * Q40 PS/2 keyboard controller driver for Linux/m68k + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#define DRV_NAME "q40kbd" + +MODULE_AUTHOR("Vojtech Pavlik "); +MODULE_DESCRIPTION("Q40 PS/2 keyboard controller driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); + +struct q40kbd { + struct serio *port; + spinlock_t lock; +}; + +static irqreturn_t q40kbd_interrupt(int irq, void *dev_id) +{ + struct q40kbd *q40kbd = dev_id; + + guard(spinlock_irqsave)(&q40kbd->lock); + + if (Q40_IRQ_KEYB_MASK & master_inb(INTERRUPT_REG)) + serio_interrupt(q40kbd->port, master_inb(KEYCODE_REG), 0); + + master_outb(-1, KEYBOARD_UNLOCK_REG); + + return IRQ_HANDLED; +} + +/* + * q40kbd_flush() flushes all data that may be in the keyboard buffers + */ + +static void q40kbd_flush(struct q40kbd *q40kbd) +{ + int maxread = 100; + + guard(spinlock_irqsave)(&q40kbd->lock); + + while (maxread-- && (Q40_IRQ_KEYB_MASK & master_inb(INTERRUPT_REG))) + master_inb(KEYCODE_REG); +} + +static void q40kbd_stop(void) +{ + master_outb(0, KEY_IRQ_ENABLE_REG); + master_outb(-1, KEYBOARD_UNLOCK_REG); +} + +/* + * q40kbd_open() is called when a port is open by the higher layer. + * It allocates the interrupt and enables in in the chip. + */ + +static int q40kbd_open(struct serio *port) +{ + struct q40kbd *q40kbd = port->port_data; + + q40kbd_flush(q40kbd); + + /* off we go */ + master_outb(-1, KEYBOARD_UNLOCK_REG); + master_outb(1, KEY_IRQ_ENABLE_REG); + + return 0; +} + +static void q40kbd_close(struct serio *port) +{ + struct q40kbd *q40kbd = port->port_data; + + q40kbd_stop(); + q40kbd_flush(q40kbd); +} + +static int q40kbd_probe(struct platform_device *pdev) +{ + struct q40kbd *q40kbd; + struct serio *port; + int error; + + q40kbd = kzalloc_obj(*q40kbd); + port = kzalloc_obj(*port); + if (!q40kbd || !port) { + error = -ENOMEM; + goto err_free_mem; + } + + q40kbd->port = port; + spin_lock_init(&q40kbd->lock); + + port->id.type = SERIO_8042; + port->open = q40kbd_open; + port->close = q40kbd_close; + port->port_data = q40kbd; + port->dev.parent = &pdev->dev; + strscpy(port->name, "Q40 Kbd Port", sizeof(port->name)); + strscpy(port->phys, "Q40", sizeof(port->phys)); + + q40kbd_stop(); + + error = request_irq(Q40_IRQ_KEYBOARD, q40kbd_interrupt, 0, + DRV_NAME, q40kbd); + if (error) { + dev_err(&pdev->dev, "Can't get irq %d.\n", Q40_IRQ_KEYBOARD); + goto err_free_mem; + } + + serio_register_port(q40kbd->port); + + platform_set_drvdata(pdev, q40kbd); + printk(KERN_INFO "serio: Q40 kbd registered\n"); + + return 0; + +err_free_mem: + kfree(port); + kfree(q40kbd); + return error; +} + +static void q40kbd_remove(struct platform_device *pdev) +{ + struct q40kbd *q40kbd = platform_get_drvdata(pdev); + + /* + * q40kbd_close() will be called as part of unregistering + * and will ensure that IRQ is turned off, so it is safe + * to unregister port first and free IRQ later. + */ + serio_unregister_port(q40kbd->port); + free_irq(Q40_IRQ_KEYBOARD, q40kbd); + kfree(q40kbd); +} + +static struct platform_driver q40kbd_driver = { + .driver = { + .name = "q40kbd", + }, + .remove = q40kbd_remove, +}; + +module_platform_driver_probe(q40kbd_driver, q40kbd_probe); -- cgit v1.3.1