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/misc/pcspkr.c | 134 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 drivers/input/misc/pcspkr.c (limited to 'drivers/input/misc/pcspkr.c') diff --git a/drivers/input/misc/pcspkr.c b/drivers/input/misc/pcspkr.c new file mode 100644 index 000000000..046780840 --- /dev/null +++ b/drivers/input/misc/pcspkr.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PC Speaker beeper driver for Linux + * + * Copyright (c) 2002 Vojtech Pavlik + * Copyright (c) 1992 Orest Zborowski + */ + + +#include +#include +#include +#include +#include +#include +#include + +MODULE_AUTHOR("Vojtech Pavlik "); +MODULE_DESCRIPTION("PC Speaker beeper driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:pcspkr"); + +static int pcspkr_event(struct input_dev *dev, unsigned int type, + unsigned int code, int value) +{ + unsigned int count = 0; + unsigned long flags; + + if (type != EV_SND) + return -EINVAL; + + switch (code) { + case SND_BELL: + if (value) + value = 1000; + break; + case SND_TONE: + break; + default: + return -EINVAL; + } + + if (value > 20 && value < 32767) + count = PIT_TICK_RATE / value; + + raw_spin_lock_irqsave(&i8253_lock, flags); + + if (count) { + /* set command for counter 2, 2 byte write */ + outb_p(0xB6, 0x43); + /* select desired HZ */ + outb_p(count & 0xff, 0x42); + outb((count >> 8) & 0xff, 0x42); + /* enable counter 2 */ + outb_p(inb_p(0x61) | 3, 0x61); + } else { + /* disable counter 2 */ + outb(inb_p(0x61) & 0xFC, 0x61); + } + + raw_spin_unlock_irqrestore(&i8253_lock, flags); + + return 0; +} + +static int pcspkr_probe(struct platform_device *dev) +{ + struct input_dev *pcspkr_dev; + int err; + + pcspkr_dev = input_allocate_device(); + if (!pcspkr_dev) + return -ENOMEM; + + pcspkr_dev->name = "PC Speaker"; + pcspkr_dev->phys = "isa0061/input0"; + pcspkr_dev->id.bustype = BUS_ISA; + pcspkr_dev->id.vendor = 0x001f; + pcspkr_dev->id.product = 0x0001; + pcspkr_dev->id.version = 0x0100; + pcspkr_dev->dev.parent = &dev->dev; + + pcspkr_dev->evbit[0] = BIT_MASK(EV_SND); + pcspkr_dev->sndbit[0] = BIT_MASK(SND_BELL) | BIT_MASK(SND_TONE); + pcspkr_dev->event = pcspkr_event; + + err = input_register_device(pcspkr_dev); + if (err) { + input_free_device(pcspkr_dev); + return err; + } + + platform_set_drvdata(dev, pcspkr_dev); + + return 0; +} + +static void pcspkr_remove(struct platform_device *dev) +{ + struct input_dev *pcspkr_dev = platform_get_drvdata(dev); + + input_unregister_device(pcspkr_dev); + /* turn off the speaker */ + pcspkr_event(NULL, EV_SND, SND_BELL, 0); +} + +static int pcspkr_suspend(struct device *dev) +{ + pcspkr_event(NULL, EV_SND, SND_BELL, 0); + + return 0; +} + +static void pcspkr_shutdown(struct platform_device *dev) +{ + /* turn off the speaker */ + pcspkr_event(NULL, EV_SND, SND_BELL, 0); +} + +static const struct dev_pm_ops pcspkr_pm_ops = { + .suspend = pcspkr_suspend, +}; + +static struct platform_driver pcspkr_platform_driver = { + .driver = { + .name = "pcspkr", + .pm = &pcspkr_pm_ops, + }, + .probe = pcspkr_probe, + .remove = pcspkr_remove, + .shutdown = pcspkr_shutdown, +}; +module_platform_driver(pcspkr_platform_driver); + -- cgit v1.3.1