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, 168 insertions, 0 deletions

diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
new file mode 100644
index 000000000..1cf1a9895
--- /dev/null
+++ b/drivers/ssb/Kconfig
@@ -0,0 +1,168 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SSB_POSSIBLE
+	bool
+	depends on HAS_IOMEM && HAS_DMA
+	default y
+
+menuconfig SSB
+	tristate "Sonics Silicon Backplane support"
+	depends on SSB_POSSIBLE
+	help
+	  Support for the Sonics Silicon Backplane bus.
+	  You only need to enable this option, if you are
+	  configuring a kernel for an embedded system with
+	  this bus.
+	  It will be auto-selected if needed in other
+	  environments.
+
+	  The module will be called ssb.
+
+	  If unsure, say N.
+
+if SSB
+
+# Common SPROM support routines
+config SSB_SPROM
+	bool
+
+# Support for Block-I/O. SELECT this from the driver that needs it.
+config SSB_BLOCKIO
+	bool
+	depends on SSB
+
+config SSB_PCIHOST_POSSIBLE
+	bool
+	depends on SSB && (PCI = y || PCI = SSB) && (PCI_DRIVERS_LEGACY || !MIPS)
+	default y
+
+config SSB_PCIHOST
+	bool "Support for SSB on PCI-bus host"
+	depends on SSB_PCIHOST_POSSIBLE
+	select SSB_SPROM
+	default y
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a PCI device.
+
+	  If unsure, say Y
+
+config SSB_B43_PCI_BRIDGE
+	bool
+	depends on SSB_PCIHOST
+	default n
+
+config SSB_PCMCIAHOST_POSSIBLE
+	bool
+	depends on SSB && (PCMCIA = y || PCMCIA = SSB)
+	default y
+
+config SSB_PCMCIAHOST
+	bool "Support for SSB on PCMCIA-bus host"
+	depends on SSB_PCMCIAHOST_POSSIBLE
+	select SSB_SPROM
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a PCMCIA device.
+
+	  If unsure, say N
+
+config SSB_SDIOHOST_POSSIBLE
+	bool
+	depends on SSB && (MMC = y || MMC = SSB)
+	default y
+
+config SSB_SDIOHOST
+	bool "Support for SSB on SDIO-bus host"
+	depends on SSB_SDIOHOST_POSSIBLE
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a SDIO device.
+
+	  If unsure, say N
+
+config SSB_HOST_SOC
+	bool "Support for SSB bus on SoC"
+	depends on SSB && BCM47XX_NVRAM
+	select SSB_SPROM
+	help
+	  Host interface for a SSB directly mapped into memory. This is
+	  for some Broadcom SoCs from the BCM47xx and BCM53xx lines.
+
+	  If unsure, say N
+
+config SSB_SERIAL
+	bool
+	depends on SSB
+	# ChipCommon and ExtIf serial support routines.
+
+config SSB_DRIVER_PCICORE_POSSIBLE
+	bool
+	depends on SSB_PCIHOST
+	default y
+
+config SSB_DRIVER_PCICORE
+	bool "SSB PCI core driver"
+	depends on SSB_DRIVER_PCICORE_POSSIBLE
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom PCI core.
+
+	  If unsure, say Y
+
+config SSB_PCICORE_HOSTMODE
+	bool "Hostmode support for SSB PCI core"
+	depends on SSB_DRIVER_PCICORE && SSB_DRIVER_MIPS && SSB = y
+	help
+	  PCIcore hostmode operation (external PCI bus).
+
+config SSB_DRIVER_MIPS
+	bool "SSB Broadcom MIPS core driver"
+	depends on SSB && MIPS
+	select SSB_SERIAL
+	select SSB_SFLASH
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom MIPS core.
+
+	  If unsure, say N
+
+config SSB_SFLASH
+	bool "SSB serial flash support"
+	depends on SSB_DRIVER_MIPS
+	default y
+
+# Assumption: We are on embedded, if we compile the MIPS core.
+config SSB_EMBEDDED
+	bool
+	depends on SSB_DRIVER_MIPS
+	depends on PCI=n || SSB_PCICORE_HOSTMODE
+	default y
+
+config SSB_DRIVER_EXTIF
+	bool "SSB Broadcom EXTIF core driver"
+	depends on SSB_DRIVER_MIPS
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom EXTIF core.
+
+	  If unsure, say N
+
+config SSB_DRIVER_GIGE
+	bool "SSB Broadcom Gigabit Ethernet driver"
+	depends on SSB_PCIHOST_POSSIBLE && SSB_EMBEDDED && MIPS
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom Gigabit Ethernet.
+
+	  If unsure, say N
+
+config SSB_DRIVER_GPIO
+	bool "SSB GPIO driver"
+	depends on SSB && GPIOLIB
+	select IRQ_DOMAIN if SSB_EMBEDDED
+	help
+	  Driver to provide access to the GPIO pins on the bus.
+
+	  If unsure, say N
+
+endif # SSB