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, 97 insertions, 0 deletions

diff --git a/drivers/usb/dwc2/Kconfig b/drivers/usb/dwc2/Kconfig
new file mode 100644
index 000000000..d7af55a8e
--- /dev/null
+++ b/drivers/usb/dwc2/Kconfig
@@ -0,0 +1,97 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_DWC2
+	tristate "DesignWare USB2 DRD Core Support"
+	depends on HAS_DMA
+	depends on USB || USB_GADGET
+	depends on HAS_IOMEM
+	select USB_ROLE_SWITCH
+	help
+	  Say Y here if your system has a Dual Role Hi-Speed USB
+	  controller based on the DesignWare HSOTG IP Core.
+
+	  For host mode, if you choose to build the driver as dynamically
+	  linked modules, the core module will be called dwc2.ko, the PCI
+	  bus interface module (if you have a PCI bus system) will be
+	  called dwc2_pci.ko, and the platform interface module (for
+	  controllers directly connected to the CPU) will be called
+	  dwc2_platform.ko. For all modes(host, gadget and dual-role), there
+	  will be an additional module named dwc2.ko.
+
+if USB_DWC2
+
+choice
+	prompt "DWC2 Mode Selection"
+	default USB_DWC2_DUAL_ROLE if (USB && USB_GADGET)
+	default USB_DWC2_HOST if (USB && !USB_GADGET)
+	default USB_DWC2_PERIPHERAL if (!USB && USB_GADGET)
+
+config USB_DWC2_HOST
+	bool "Host only mode"
+	depends on USB=y || (USB_DWC2=m && USB)
+	help
+	  The Designware USB2.0 high-speed host controller
+	  integrated into many SoCs. Select this option if you want the
+	  driver to operate in Host-only mode.
+
+comment "Gadget/Dual-role mode requires USB Gadget support to be enabled"
+
+config USB_DWC2_PERIPHERAL
+	bool "Gadget only mode"
+	depends on USB_GADGET=y || USB_GADGET=USB_DWC2
+	help
+	  The Designware USB2.0 high-speed gadget controller
+	  integrated into many SoCs. Select this option if you want the
+	  driver to operate in Peripheral-only mode. This option requires
+	  USB_GADGET to be enabled.
+
+config USB_DWC2_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on (USB=y && USB_GADGET=y) || (USB_DWC2=m && USB && USB_GADGET)
+	help
+	  Select this option if you want the driver to work in a dual-role
+	  mode. In this mode both host and gadget features are enabled, and
+	  the role will be determined by the cable that gets plugged-in. This
+	  option requires USB_GADGET to be enabled.
+endchoice
+
+config USB_DWC2_PCI
+	tristate "DWC2 PCI"
+	depends on USB_PCI
+	depends on USB_GADGET || !USB_GADGET
+	select NOP_USB_XCEIV
+	help
+	  The Designware USB2.0 PCI interface module for controllers
+	  connected to a PCI bus.
+
+config USB_DWC2_DEBUG
+	bool "Enable Debugging Messages"
+	help
+	  Say Y here to enable debugging messages in the DWC2 Driver.
+
+config USB_DWC2_VERBOSE
+	bool "Enable Verbose Debugging Messages"
+	depends on USB_DWC2_DEBUG
+	help
+	  Say Y here to enable verbose debugging messages in the DWC2 Driver.
+	  WARNING: Enabling this will quickly fill your message log.
+	  If in doubt, say N.
+
+config USB_DWC2_TRACK_MISSED_SOFS
+	bool "Enable Missed SOF Tracking"
+	help
+	  Say Y here to enable logging of missed SOF events to the dmesg log.
+	  WARNING: This feature is still experimental.
+	  If in doubt, say N.
+
+config USB_DWC2_DEBUG_PERIODIC
+	bool "Enable Debugging Messages For Periodic Transfers"
+	depends on USB_DWC2_DEBUG || USB_DWC2_VERBOSE
+	default y
+	help
+	  Say N here to disable (verbose) debugging messages to be
+	  logged for periodic transfers. This allows better debugging of
+	  non-periodic transfers, but of course the debug logs will be
+	  incomplete. Note that this also disables some debug messages
+	  for which the transfer type cannot be deduced.
+endif