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 --- include/vdso/unaligned.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 include/vdso/unaligned.h (limited to 'include/vdso/unaligned.h') diff --git a/include/vdso/unaligned.h b/include/vdso/unaligned.h new file mode 100644 index 000000000..9076483c9 --- /dev/null +++ b/include/vdso/unaligned.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __VDSO_UNALIGNED_H +#define __VDSO_UNALIGNED_H + +#include + +/** + * __get_unaligned_t - read an unaligned value from memory. + * @type: the type to load from the pointer. + * @ptr: the pointer to load from. + * + * Use memcpy to affect an unaligned type sized load avoiding undefined behavior + * from approaches like type punning that require -fno-strict-aliasing in order + * to be correct. As type may be const, use __unqual_scalar_typeof to map to a + * non-const type - you can't memcpy into a const type. The + * __get_unaligned_ctrl_type gives __unqual_scalar_typeof its required + * expression rather than type, a pointer is used to avoid warnings about mixing + * the use of 0 and NULL. The void* cast silences ubsan warnings. + */ +#define __get_unaligned_t(type, ptr) ({ \ + type *__get_unaligned_ctrl_type __always_unused = NULL; \ + __unqual_scalar_typeof(*__get_unaligned_ctrl_type) __get_unaligned_val; \ + __builtin_memcpy(&__get_unaligned_val, (void *)(ptr), \ + sizeof(__get_unaligned_val)); \ + __get_unaligned_val; \ +}) + +/** + * __put_unaligned_t - write an unaligned value to memory. + * @type: the type of the value to store. + * @val: the value to store. + * @ptr: the pointer to store to. + * + * Use memcpy to affect an unaligned type sized store avoiding undefined + * behavior from approaches like type punning that require -fno-strict-aliasing + * in order to be correct. The void* cast silences ubsan warnings. + */ +#define __put_unaligned_t(type, val, ptr) do { \ + type __put_unaligned_val = (val); \ + __builtin_memcpy((void *)(ptr), &__put_unaligned_val, \ + sizeof(__put_unaligned_val)); \ +} while (0) + +#endif /* __VDSO_UNALIGNED_H */ -- cgit v1.3.1