x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

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 <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
new file mode 100644
index 000000000..8efbcf699
--- /dev/null
+++ b/drivers/firmware/efi/Makefile
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for linux kernel
+#
+
+#
+# ARM64 maps efi runtime services in userspace addresses
+# which don't have KASAN shadow. So dereference of these addresses
+# in efi_call_virt() will cause crash if this code instrumented.
+#
+KASAN_SANITIZE_runtime-wrappers.o	:= n
+
+obj-$(CONFIG_ACPI_BGRT) 		+= efi-bgrt.o
+obj-$(CONFIG_EFI)			+= efi.o vars.o reboot.o memattr.o tpm.o
+obj-$(CONFIG_EFI)			+= memmap.o
+ifneq ($(CONFIG_EFI_CAPSULE_LOADER),)
+obj-$(CONFIG_EFI)			+= capsule.o
+endif
+obj-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= fdtparams.o
+obj-$(CONFIG_EFI_ESRT)			+= esrt.o
+obj-$(CONFIG_EFI_VARS_PSTORE)		+= efi-pstore.o
+obj-$(CONFIG_UEFI_CPER)			+= cper.o cper_cxl.o
+obj-$(CONFIG_EFI_RUNTIME_WRAPPERS)	+= runtime-wrappers.o
+subdir-$(CONFIG_EFI_STUB)		+= libstub
+obj-$(CONFIG_EFI_BOOTLOADER_CONTROL)	+= efibc.o
+obj-$(CONFIG_EFI_TEST)			+= test/
+obj-$(CONFIG_EFI_DEV_PATH_PARSER)	+= dev-path-parser.o
+obj-$(CONFIG_APPLE_PROPERTIES)		+= apple-properties.o
+obj-$(CONFIG_EFI_RCI2_TABLE)		+= rci2-table.o
+obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE)	+= embedded-firmware.o
+obj-$(CONFIG_LOAD_UEFI_KEYS)		+= mokvar-table.o
+obj-$(CONFIG_OVMF_DEBUG_LOG)		+= ovmf-debug-log.o
+
+obj-$(CONFIG_SYSFB)			+= sysfb_efi.o
+
+arm-obj-$(CONFIG_EFI)			:= efi-init.o arm-runtime.o
+obj-$(CONFIG_ARM)			+= $(arm-obj-y)
+obj-$(CONFIG_ARM64)			+= $(arm-obj-y)
+riscv-obj-$(CONFIG_EFI)			:= efi-init.o riscv-runtime.o
+obj-$(CONFIG_RISCV)			+= $(riscv-obj-y)
+obj-$(CONFIG_EFI_CAPSULE_LOADER)	+= capsule-loader.o
+obj-$(CONFIG_EFI_EARLYCON)		+= earlycon.o
+obj-$(CONFIG_UEFI_CPER_ARM)		+= cper-arm.o
+obj-$(CONFIG_UEFI_CPER_X86)		+= cper-x86.o
+obj-$(CONFIG_UNACCEPTED_MEMORY)		+= unaccepted_memory.o
+obj-$(CONFIG_TEE_STMM_EFI)		+= stmm/tee_stmm_efi.o