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, 50 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
new file mode 100644
index 000000000..0834a9a12
--- /dev/null
+++ b/arch/powerpc/sysdev/Makefile
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-2.0
+
+mpic-msi-obj-$(CONFIG_PCI_MSI)	+= mpic_msi.o mpic_u3msi.o
+obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y)
+obj-$(CONFIG_MPIC_TIMER)        += mpic_timer.o
+obj-$(CONFIG_FSL_MPIC_TIMER_WAKEUP)	+= fsl_mpic_timer_wakeup.o
+mpic-msgr-obj-$(CONFIG_MPIC_MSGR)	+= mpic_msgr.o
+obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y) $(mpic-msgr-obj-y)
+obj-$(CONFIG_PPC_EPAPR_HV_PIC)	+= ehv_pic.o
+fsl-msi-obj-$(CONFIG_PCI_MSI)	+= fsl_msi.o
+obj-$(CONFIG_PPC_MSI_BITMAP)	+= msi_bitmap.o
+
+obj-$(CONFIG_PPC_MPC106)	+= grackle.o
+obj-$(CONFIG_PPC_DCR_NATIVE)	+= dcr-low.o
+obj-$(CONFIG_U3_DART)		+= dart_iommu.o
+obj-$(CONFIG_MMIO_NVRAM)	+= mmio_nvram.o
+obj-$(CONFIG_FSL_SOC)		+= fsl_soc.o fsl_mpic_err.o
+obj-$(CONFIG_FSL_PCI)		+= fsl_pci.o $(fsl-msi-obj-y)
+obj-$(CONFIG_FSL_PMC)		+= fsl_pmc.o
+obj-$(CONFIG_FSL_CORENET_RCPM)	+= fsl_rcpm.o
+obj-$(CONFIG_FSL_LBC)		+= fsl_lbc.o
+obj-$(CONFIG_FSL_GTM)		+= fsl_gtm.o
+obj-$(CONFIG_FSL_RIO)		+= fsl_rio.o fsl_rmu.o
+obj-$(CONFIG_TSI108_BRIDGE)	+= tsi108_pci.o tsi108_dev.o
+obj-$(CONFIG_RTC_DRV_CMOS)	+= rtc_cmos_setup.o
+
+obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o
+obj-$(CONFIG_PPC_I8259)		+= i8259.o
+obj-$(CONFIG_IPIC)		+= ipic.o
+obj-$(CONFIG_OF_RTC)		+= of_rtc.o
+
+obj-$(CONFIG_CPM)		+= cpm_common.o
+obj-$(CONFIG_CPM2)		+= cpm2.o cpm2_pic.o cpm_gpio.o
+obj-$(CONFIG_8xx_GPIO)		+= cpm_gpio.o
+obj-$(CONFIG_QUICC_ENGINE)	+= cpm_common.o
+obj-$(CONFIG_PPC_DCR)		+= dcr.o
+
+obj-$(CONFIG_PPC_MPC512x)	+= mpc5xxx_clocks.o
+obj-$(CONFIG_PPC_MPC52xx)	+= mpc5xxx_clocks.o
+
+ifdef CONFIG_SUSPEND
+obj-$(CONFIG_PPC_BOOK3S_32)	+= 6xx-suspend.o
+endif
+
+obj-$(CONFIG_PPC_EARLY_DEBUG_MEMCONS)	+= udbg_memcons.o
+
+obj-$(CONFIG_PPC_XICS)		+= xics/
+obj-$(CONFIG_PPC_XIVE)		+= xive/
+
+obj-$(CONFIG_GE_FPGA)		+= ge/