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, 113 insertions, 0 deletions

diff --git a/drivers/misc/mei/Kconfig b/drivers/misc/mei/Kconfig
new file mode 100644
index 000000000..2d1bc5b4d
--- /dev/null
+++ b/drivers/misc/mei/Kconfig
@@ -0,0 +1,113 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2003-2019, Intel Corporation. All rights reserved.
+config INTEL_MEI
+	tristate "Intel Management Engine Interface"
+	depends on PCI
+	depends on X86 || DRM_XE!=n || COMPILE_TEST
+	default X86_64 || MATOM
+	help
+	  The Intel Management Engine (Intel ME) provides Manageability,
+	  Security and Media services for system containing Intel chipsets.
+	  if selected /dev/mei misc device will be created.
+
+	  For more information see
+	  <https://software.intel.com/en-us/manageability/>
+
+if INTEL_MEI
+
+config INTEL_MEI_ME
+	tristate "ME Enabled Intel Chipsets"
+	default y
+	help
+	  MEI support for ME Enabled Intel chipsets.
+
+	  Supported Chipsets are:
+	  7 Series Chipset Family
+	  6 Series Chipset Family
+	  5 Series Chipset Family
+	  4 Series Chipset Family
+	  Mobile 4 Series Chipset Family
+	  ICH9
+	  82946GZ/GL
+	  82G35 Express
+	  82Q963/Q965
+	  82P965/G965
+	  Mobile PM965/GM965
+	  Mobile GME965/GLE960
+	  82Q35 Express
+	  82G33/G31/P35/P31 Express
+	  82Q33 Express
+	  82X38/X48 Express
+
+config INTEL_MEI_TXE
+	tristate "Intel Trusted Execution Environment with ME Interface"
+	help
+	  MEI Support for Trusted Execution Environment device on Intel SoCs
+
+	  Supported SoCs:
+	  Intel Bay Trail
+
+config INTEL_MEI_GSC
+	tristate "Intel MEI GSC embedded device"
+	depends on INTEL_MEI_ME
+	depends on DRM_I915!=n || DRM_XE!=n || COMPILE_TEST
+	help
+	  Intel auxiliary driver for GSC devices embedded in Intel graphics devices.
+
+	  An MEI device here called GSC can be embedded in an
+	  Intel graphics devices, to support a range of chassis
+	  tasks such as graphics card firmware update and security
+	  tasks.
+
+config INTEL_MEI_CSC
+	tristate "Intel MEI CSC embedded device"
+	depends on INTEL_MEI_ME
+	help
+	  Intel PCI driver for the chassis controller embedded in Intel graphics devices.
+
+	  An MEI device here called CSC can be embedded in discrete
+	  Intel graphics devices, to support a range of chassis
+	  tasks such as graphics card firmware update and security
+	  tasks.
+
+config INTEL_MEI_VSC_HW
+	tristate "Intel visual sensing controller device transport driver"
+	depends on ACPI && SPI
+	depends on GPIOLIB || COMPILE_TEST
+	help
+	  Intel SPI transport driver between host and Intel visual sensing
+	  controller (IVSC) device.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called mei-vsc-hw.
+
+config INTEL_MEI_VSC
+	tristate "Intel visual sensing controller device with ME interface"
+	depends on INTEL_MEI_VSC_HW
+	help
+	  Intel MEI over SPI driver for Intel visual sensing controller
+	  (IVSC) device embedded in IA platform. It supports camera sharing
+	  between IVSC for context sensing and IPU for typical media usage.
+	  Select this config should enable transport layer for IVSC device.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called mei-vsc.
+
+config INTEL_MEI_LB
+	tristate "Intel Late Binding (LB) support on ME Interface"
+	depends on INTEL_MEI_ME
+	depends on DRM_XE!=n || COMPILE_TEST
+	help
+	  Enable support for Intel Late Binding (LB) via the MEI interface.
+
+	  Late Binding is a method for applying firmware updates at runtime,
+	  allowing the Intel Xe driver to load firmware payloads such as
+	  fan controller or voltage regulator. These firmware updates are
+	  authenticated and versioned, and do not require firmware flashing
+	  or system reboot.
+
+source "drivers/misc/mei/hdcp/Kconfig"
+source "drivers/misc/mei/pxp/Kconfig"
+source "drivers/misc/mei/gsc_proxy/Kconfig"
+
+endif