From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- drivers/misc/dummy-irq.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 drivers/misc/dummy-irq.c (limited to 'drivers/misc/dummy-irq.c') diff --git a/drivers/misc/dummy-irq.c b/drivers/misc/dummy-irq.c new file mode 100644 index 000000000..fe3bfcb31 --- /dev/null +++ b/drivers/misc/dummy-irq.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Dummy IRQ handler driver. + * + * This module only registers itself as a handler that is specified to it + * by the 'irq' parameter. + * + * The sole purpose of this module is to help with debugging of systems on + * which spurious IRQs would happen on disabled IRQ vector. + * + * Copyright (C) 2013 Jiri Kosina + */ + +#include +#include +#include + +static int irq = -1; + +static irqreturn_t dummy_interrupt(int irq, void *dev_id) +{ + static int count = 0; + + if (count == 0) { + printk(KERN_INFO "dummy-irq: interrupt occurred on IRQ %d\n", + irq); + count++; + } + + return IRQ_NONE; +} + +static int __init dummy_irq_init(void) +{ + if (irq < 0) { + printk(KERN_ERR "dummy-irq: no IRQ given. Use irq=N\n"); + return -EIO; + } + if (request_irq(irq, &dummy_interrupt, IRQF_SHARED, "dummy_irq", &irq)) { + printk(KERN_ERR "dummy-irq: cannot register IRQ %d\n", irq); + return -EIO; + } + printk(KERN_INFO "dummy-irq: registered for IRQ %d\n", irq); + return 0; +} + +static void __exit dummy_irq_exit(void) +{ + printk(KERN_INFO "dummy-irq unloaded\n"); + free_irq(irq, &irq); +} + +module_init(dummy_irq_init); +module_exit(dummy_irq_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jiri Kosina"); +module_param_hw(irq, uint, irq, 0444); +MODULE_PARM_DESC(irq, "The IRQ to register for"); +MODULE_DESCRIPTION("Dummy IRQ handler driver"); -- cgit v1.3.1