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/evged.c | 195 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 195 insertions(+) create mode 100644 drivers/acpi/evged.c (limited to 'drivers/acpi/evged.c') diff --git a/drivers/acpi/evged.c b/drivers/acpi/evged.c new file mode 100644 index 000000000..5c35cbc7f --- /dev/null +++ b/drivers/acpi/evged.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Generic Event Device for ACPI. + * + * Copyright (c) 2016, The Linux Foundation. All rights reserved. + * + * Generic Event Device allows platforms to handle interrupts in ACPI + * ASL statements. It follows very similar to _EVT method approach + * from GPIO events. All interrupts are listed in _CRS and the handler + * is written in _EVT method. Here is an example. + * + * Device (GED0) + * { + * + * Name (_HID, "ACPI0013") + * Name (_UID, 0) + * Method (_CRS, 0x0, Serialized) + * { + * Name (RBUF, ResourceTemplate () + * { + * Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , ) + * {123} + * } + * }) + * + * Method (_EVT, 1) { + * if (Lequal(123, Arg0)) + * { + * } + * } + * } + */ + +#include +#include +#include +#include +#include +#include + +#define MODULE_NAME "acpi-ged" + +struct acpi_ged_device { + struct device *dev; + struct list_head event_list; +}; + +struct acpi_ged_event { + struct list_head node; + struct device *dev; + unsigned int gsi; + unsigned int irq; + acpi_handle handle; +}; + +static irqreturn_t acpi_ged_irq_handler(int irq, void *data) +{ + struct acpi_ged_event *event = data; + acpi_status acpi_ret; + + acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi); + if (ACPI_FAILURE(acpi_ret)) + dev_err_once(event->dev, "IRQ method execution failed\n"); + + return IRQ_HANDLED; +} + +static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares, + void *context) +{ + struct acpi_ged_event *event; + unsigned int irq; + unsigned int gsi; + unsigned int irqflags = IRQF_ONESHOT; + struct acpi_ged_device *geddev = context; + struct device *dev = geddev->dev; + acpi_handle handle = ACPI_HANDLE(dev); + acpi_handle evt_handle; + struct resource r; + struct acpi_resource_irq *p = &ares->data.irq; + struct acpi_resource_extended_irq *pext = &ares->data.extended_irq; + char ev_name[5]; + u8 trigger; + + if (ares->type == ACPI_RESOURCE_TYPE_END_TAG) + return AE_OK; + + if (!acpi_dev_resource_interrupt(ares, 0, &r)) { + dev_err(dev, "unable to parse IRQ resource\n"); + return AE_ERROR; + } + if (ares->type == ACPI_RESOURCE_TYPE_IRQ) { + gsi = p->interrupts[0]; + trigger = p->triggering; + } else { + gsi = pext->interrupts[0]; + trigger = pext->triggering; + } + + irq = r.start; + + switch (gsi) { + case 0 ... 255: + sprintf(ev_name, "_%c%02X", + trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi); + + if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle))) + break; + fallthrough; + default: + if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle))) + break; + + dev_err(dev, "cannot locate _EVT method\n"); + return AE_ERROR; + } + + event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL); + if (!event) + return AE_ERROR; + + event->gsi = gsi; + event->dev = dev; + event->irq = irq; + event->handle = evt_handle; + + if (r.flags & IORESOURCE_IRQ_SHAREABLE) + irqflags |= IRQF_SHARED; + + if (request_threaded_irq(irq, NULL, acpi_ged_irq_handler, + irqflags, "ACPI:Ged", event)) { + dev_err(dev, "failed to setup event handler for irq %u\n", irq); + return AE_ERROR; + } + + dev_dbg(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq); + list_add_tail(&event->node, &geddev->event_list); + return AE_OK; +} + +static int ged_probe(struct platform_device *pdev) +{ + struct acpi_ged_device *geddev; + acpi_status acpi_ret; + + geddev = devm_kzalloc(&pdev->dev, sizeof(*geddev), GFP_KERNEL); + if (!geddev) + return -ENOMEM; + + geddev->dev = &pdev->dev; + INIT_LIST_HEAD(&geddev->event_list); + acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS", + acpi_ged_request_interrupt, geddev); + if (ACPI_FAILURE(acpi_ret)) { + dev_err(&pdev->dev, "unable to parse the _CRS record\n"); + return -EINVAL; + } + platform_set_drvdata(pdev, geddev); + + return 0; +} + +static void ged_shutdown(struct platform_device *pdev) +{ + struct acpi_ged_device *geddev = platform_get_drvdata(pdev); + struct acpi_ged_event *event, *next; + + list_for_each_entry_safe(event, next, &geddev->event_list, node) { + free_irq(event->irq, event); + list_del(&event->node); + dev_dbg(geddev->dev, "GED releasing GSI %u @ IRQ %u\n", + event->gsi, event->irq); + } +} + +static void ged_remove(struct platform_device *pdev) +{ + ged_shutdown(pdev); +} + +static const struct acpi_device_id ged_acpi_ids[] = { + {"ACPI0013"}, + {}, +}; + +static struct platform_driver ged_driver = { + .probe = ged_probe, + .remove = ged_remove, + .shutdown = ged_shutdown, + .driver = { + .name = MODULE_NAME, + .acpi_match_table = ACPI_PTR(ged_acpi_ids), + }, +}; +builtin_platform_driver(ged_driver); -- cgit v1.3.1