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, 91 insertions, 0 deletions

diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
new file mode 100644
index 000000000..174580c12
--- /dev/null
+++ b/drivers/usb/host/Makefile
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for USB Host Controller Drivers
+#
+
+# tell define_trace.h where to find the xhci trace header
+CFLAGS_xhci-trace.o := -I$(src)
+
+fhci-y := fhci-hcd.o fhci-hub.o fhci-q.o
+fhci-y += fhci-mem.o fhci-tds.o fhci-sched.o
+
+fhci-$(CONFIG_FHCI_DEBUG) += fhci-dbg.o
+
+xhci-hcd-y := xhci.o xhci-mem.o xhci-ext-caps.o
+xhci-hcd-y += xhci-ring.o xhci-hub.o xhci-dbg.o
+xhci-hcd-y += xhci-trace.o
+
+ifneq ($(CONFIG_USB_XHCI_DBGCAP), )
+	xhci-hcd-y += xhci-dbgcap.o xhci-dbgtty.o
+endif
+
+xhci-mtk-hcd-y := xhci-mtk.o xhci-mtk-sch.o
+
+xhci-plat-hcd-y := xhci-plat.o
+ifneq ($(CONFIG_USB_XHCI_MVEBU), )
+	xhci-plat-hcd-y		+= xhci-mvebu.o
+endif
+ifneq ($(CONFIG_DEBUG_FS),)
+	xhci-hcd-y		+= xhci-debugfs.o
+endif
+
+xhci-rcar-hcd-y				+= xhci-rcar.o
+xhci-rcar-hcd-$(CONFIG_USB_XHCI_RZV2M)	+= xhci-rzv2m.o
+
+ifneq ($(CONFIG_USB_XHCI_SIDEBAND),)
+	xhci-hcd-y		+= xhci-sideband.o
+endif
+
+obj-$(CONFIG_USB_PCI)	+= pci-quirks.o
+
+obj-$(CONFIG_USB_EHCI_HCD)	+= ehci-hcd.o
+obj-$(CONFIG_USB_EHCI_PCI)	+= ehci-pci.o
+obj-$(CONFIG_USB_EHCI_HCD_PLATFORM)	+= ehci-platform.o
+obj-$(CONFIG_USB_EHCI_HCD_NPCM7XX)	+= ehci-npcm7xx.o
+obj-$(CONFIG_USB_EHCI_HCD_OMAP)	+= ehci-omap.o
+obj-$(CONFIG_USB_EHCI_HCD_ORION)	+= ehci-orion.o
+obj-$(CONFIG_USB_EHCI_HCD_SPEAR)	+= ehci-spear.o
+obj-$(CONFIG_USB_EHCI_HCD_STI)	+= ehci-st.o
+obj-$(CONFIG_USB_EHCI_EXYNOS)	+= ehci-exynos.o
+obj-$(CONFIG_USB_EHCI_HCD_AT91) += ehci-atmel.o
+obj-$(CONFIG_USB_EHCI_BRCMSTB)	+= ehci-brcm.o
+
+obj-$(CONFIG_USB_OXU210HP_HCD)	+= oxu210hp-hcd.o
+obj-$(CONFIG_USB_ISP116X_HCD)	+= isp116x-hcd.o
+
+obj-$(CONFIG_USB_OHCI_HCD)	+= ohci-hcd.o
+obj-$(CONFIG_USB_OHCI_HCD_PCI)	+= ohci-pci.o
+obj-$(CONFIG_USB_OHCI_HCD_PLATFORM)	+= ohci-platform.o
+obj-$(CONFIG_USB_OHCI_EXYNOS)	+= ohci-exynos.o
+obj-$(CONFIG_USB_OHCI_HCD_OMAP1)	+= ohci-omap.o
+obj-$(CONFIG_USB_OHCI_HCD_SPEAR)	+= ohci-spear.o
+obj-$(CONFIG_USB_OHCI_HCD_STI)	+= ohci-st.o
+obj-$(CONFIG_USB_OHCI_HCD_AT91)	+= ohci-at91.o
+obj-$(CONFIG_USB_OHCI_HCD_S3C2410)	+= ohci-s3c2410.o
+obj-$(CONFIG_USB_OHCI_HCD_LPC32XX)	+= ohci-nxp.o
+obj-$(CONFIG_USB_OHCI_HCD_PXA27X)	+= ohci-pxa27x.o
+obj-$(CONFIG_USB_OHCI_HCD_DAVINCI)	+= ohci-da8xx.o
+obj-$(CONFIG_USB_OCTEON_HCD)	+= octeon-hcd.o
+
+obj-$(CONFIG_USB_UHCI_HCD)	+= uhci-hcd.o
+obj-$(CONFIG_USB_FHCI_HCD)	+= fhci.o
+obj-$(CONFIG_USB_XHCI_HCD)	+= xhci-hcd.o
+obj-$(CONFIG_USB_XHCI_PCI)	+= xhci-pci.o
+obj-$(CONFIG_USB_XHCI_PCI_PROM21)	+= xhci-pci-prom21.o
+obj-$(CONFIG_USB_XHCI_PCI_RENESAS)	+= xhci-pci-renesas.o
+obj-$(CONFIG_USB_XHCI_PLATFORM) += xhci-plat-hcd.o
+obj-$(CONFIG_USB_XHCI_HISTB)	+= xhci-histb.o
+obj-$(CONFIG_USB_XHCI_RCAR)	+= xhci-rcar-hcd.o
+obj-$(CONFIG_USB_XHCI_MTK)	+= xhci-mtk-hcd.o
+obj-$(CONFIG_USB_XHCI_TEGRA)	+= xhci-tegra.o
+obj-$(CONFIG_USB_SL811_HCD)	+= sl811-hcd.o
+obj-$(CONFIG_USB_SL811_CS)	+= sl811_cs.o
+obj-$(CONFIG_USB_R8A66597_HCD)	+= r8a66597-hcd.o
+obj-$(CONFIG_USB_FSL_USB2)	+= fsl-mph-dr-of.o
+obj-$(CONFIG_USB_EHCI_FSL)	+= fsl-mph-dr-of.o
+obj-$(CONFIG_USB_EHCI_FSL)	+= ehci-fsl.o
+obj-$(CONFIG_USB_EHCI_MV)	+= ehci-mv.o
+obj-$(CONFIG_USB_HCD_BCMA)	+= bcma-hcd.o
+obj-$(CONFIG_USB_HCD_SSB)	+= ssb-hcd.o
+obj-$(CONFIG_USB_MAX3421_HCD)	+= max3421-hcd.o
+obj-$(CONFIG_USB_XEN_HCD)	+= xen-hcd.o