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, 48 insertions, 0 deletions

diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
new file mode 100644
index 000000000..88cbc2a7a
--- /dev/null
+++ b/drivers/cpuidle/Makefile
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for cpuidle.
+#
+
+# Branch profiling isn't noinstr-safe
+ccflags-$(CONFIG_TRACE_BRANCH_PROFILING) += -DDISABLE_BRANCH_PROFILING
+
+obj-y += cpuidle.o driver.o governor.o sysfs.o governors/
+obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
+obj-$(CONFIG_DT_IDLE_STATES)		  += dt_idle_states.o
+obj-$(CONFIG_DT_IDLE_GENPD)		  += dt_idle_genpd.o
+obj-$(CONFIG_ARCH_HAS_CPU_RELAX)	  += poll_state.o
+obj-$(CONFIG_HALTPOLL_CPUIDLE)		  += cpuidle-haltpoll.o
+
+##################################################################################
+# ARM SoC drivers
+obj-$(CONFIG_ARM_MVEBU_V7_CPUIDLE) += cpuidle-mvebu-v7.o
+obj-$(CONFIG_ARM_BIG_LITTLE_CPUIDLE)	+= cpuidle-big_little.o
+obj-$(CONFIG_ARM_CLPS711X_CPUIDLE)	+= cpuidle-clps711x.o
+obj-$(CONFIG_ARM_HIGHBANK_CPUIDLE)	+= cpuidle-calxeda.o
+obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE)	+= cpuidle-kirkwood.o
+obj-$(CONFIG_ARM_ZYNQ_CPUIDLE)		+= cpuidle-zynq.o
+obj-$(CONFIG_ARM_U8500_CPUIDLE)         += cpuidle-ux500.o
+obj-$(CONFIG_ARM_AT91_CPUIDLE)          += cpuidle-at91.o
+obj-$(CONFIG_ARM_EXYNOS_CPUIDLE)        += cpuidle-exynos.o
+obj-$(CONFIG_ARM_CPUIDLE)		+= cpuidle-arm.o
+obj-$(CONFIG_ARM_PSCI_CPUIDLE)		+= cpuidle-psci.o
+obj-$(CONFIG_ARM_PSCI_CPUIDLE_DOMAIN)	+= cpuidle-psci-domain.o
+obj-$(CONFIG_ARM_TEGRA_CPUIDLE)		+= cpuidle-tegra.o
+obj-$(CONFIG_ARM_QCOM_SPM_CPUIDLE)	+= cpuidle-qcom-spm.o
+
+###############################################################################
+# MIPS drivers
+obj-$(CONFIG_MIPS_CPS_CPUIDLE)		+= cpuidle-cps.o
+
+###############################################################################
+# POWERPC drivers
+obj-$(CONFIG_PSERIES_CPUIDLE)		+= cpuidle-pseries.o
+obj-$(CONFIG_POWERNV_CPUIDLE)		+= cpuidle-powernv.o
+
+###############################################################################
+# RISC-V drivers
+obj-$(CONFIG_RISCV_SBI_CPUIDLE)		+= cpuidle-riscv-sbi.o
+
+###############################################################################
+# S390 drivers
+obj-$(CONFIG_S390_CPUIDLE)		+= cpuidle-s390.o