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/acpi/hed.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 drivers/acpi/hed.c (limited to 'drivers/acpi/hed.c') diff --git a/drivers/acpi/hed.c b/drivers/acpi/hed.c new file mode 100644 index 000000000..48562f53d --- /dev/null +++ b/drivers/acpi/hed.c @@ -0,0 +1,90 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ACPI Hardware Error Device (PNP0C33) Driver + * + * Copyright (C) 2010, Intel Corp. + * Author: Huang Ying + * + * ACPI Hardware Error Device is used to report some hardware errors + * notified via SCI, mainly the corrected errors. + */ + +#include +#include +#include +#include +#include +#include + +static const struct acpi_device_id acpi_hed_ids[] = { + {"PNP0C33", 0}, + {"", 0}, +}; +MODULE_DEVICE_TABLE(acpi, acpi_hed_ids); + +static bool hed_present; + +static BLOCKING_NOTIFIER_HEAD(acpi_hed_notify_list); + +int register_acpi_hed_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&acpi_hed_notify_list, nb); +} +EXPORT_SYMBOL_GPL(register_acpi_hed_notifier); + +void unregister_acpi_hed_notifier(struct notifier_block *nb) +{ + blocking_notifier_chain_unregister(&acpi_hed_notify_list, nb); +} +EXPORT_SYMBOL_GPL(unregister_acpi_hed_notifier); + +/* + * SCI to report hardware error is forwarded to the listeners of HED, + * it is used by HEST Generic Hardware Error Source with notify type + * SCI. + */ +static void acpi_hed_notify(acpi_handle handle, u32 event, void *data) +{ + blocking_notifier_call_chain(&acpi_hed_notify_list, 0, NULL); +} + +static int acpi_hed_probe(struct platform_device *pdev) +{ + int err; + + /* Only one hardware error device */ + if (hed_present) + return -EINVAL; + + err = devm_acpi_install_notify_handler(&pdev->dev, ACPI_DEVICE_NOTIFY, + acpi_hed_notify, NULL); + if (err) + return err; + + hed_present = true; + return 0; +} + +static void acpi_hed_remove(struct platform_device *pdev) +{ + hed_present = false; +} + +static struct platform_driver acpi_hed_driver = { + .probe = acpi_hed_probe, + .remove = acpi_hed_remove, + .driver = { + .name = "acpi-hardware-error-device", + .acpi_match_table = acpi_hed_ids, + }, +}; + +static int __init acpi_hed_driver_init(void) +{ + return platform_driver_register(&acpi_hed_driver); +} +subsys_initcall(acpi_hed_driver_init); + +MODULE_AUTHOR("Huang Ying"); +MODULE_DESCRIPTION("ACPI Hardware Error Device Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1