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/apm-power.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 drivers/input/apm-power.c (limited to 'drivers/input/apm-power.c') diff --git a/drivers/input/apm-power.c b/drivers/input/apm-power.c new file mode 100644 index 000000000..028fcaf4c --- /dev/null +++ b/drivers/input/apm-power.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Input Power Event -> APM Bridge + * + * Copyright (c) 2007 Richard Purdie + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +static void system_power_event(unsigned int keycode) +{ + switch (keycode) { + case KEY_SUSPEND: + apm_queue_event(APM_USER_SUSPEND); + pr_info("Requesting system suspend...\n"); + break; + default: + break; + } +} + +static void apmpower_event(struct input_handle *handle, unsigned int type, + unsigned int code, int value) +{ + /* only react on key down events */ + if (value != 1) + return; + + switch (type) { + case EV_PWR: + system_power_event(code); + break; + + default: + break; + } +} + +static int apmpower_connect(struct input_handler *handler, + struct input_dev *dev, + const struct input_device_id *id) +{ + struct input_handle *handle; + int error; + + handle = kzalloc_obj(struct input_handle); + if (!handle) + return -ENOMEM; + + handle->dev = dev; + handle->handler = handler; + handle->name = "apm-power"; + + error = input_register_handle(handle); + if (error) { + pr_err("Failed to register input power handler, error %d\n", + error); + kfree(handle); + return error; + } + + error = input_open_device(handle); + if (error) { + pr_err("Failed to open input power device, error %d\n", error); + input_unregister_handle(handle); + kfree(handle); + return error; + } + + return 0; +} + +static void apmpower_disconnect(struct input_handle *handle) +{ + input_close_device(handle); + input_unregister_handle(handle); + kfree(handle); +} + +static const struct input_device_id apmpower_ids[] = { + { + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, + .evbit = { BIT_MASK(EV_PWR) }, + }, + { }, +}; + +MODULE_DEVICE_TABLE(input, apmpower_ids); + +static struct input_handler apmpower_handler = { + .event = apmpower_event, + .connect = apmpower_connect, + .disconnect = apmpower_disconnect, + .name = "apm-power", + .id_table = apmpower_ids, +}; + +static int __init apmpower_init(void) +{ + return input_register_handler(&apmpower_handler); +} + +static void __exit apmpower_exit(void) +{ + input_unregister_handler(&apmpower_handler); +} + +module_init(apmpower_init); +module_exit(apmpower_exit); + +MODULE_AUTHOR("Richard Purdie "); +MODULE_DESCRIPTION("Input Power Event -> APM Bridge"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1