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, 49 insertions, 0 deletions

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
new file mode 100644
index 000000000..5b5cdc0d3
--- /dev/null
+++ b/drivers/char/tpm/Makefile
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the kernel tpm device drivers.
+#
+obj-$(CONFIG_TCG_TPM) += tpm.o
+tpm-y := tpm-chip.o
+tpm-y += tpm-dev-common.o
+tpm-y += tpm-dev.o
+tpm-y += tpm-interface.o
+tpm-y += tpm1-cmd.o
+tpm-y += tpm2-cmd.o
+tpm-y += tpmrm-dev.o
+tpm-y += tpm2-space.o
+tpm-y += tpm-sysfs.o
+tpm-y += eventlog/common.o
+tpm-y += eventlog/tpm1.o
+tpm-y += eventlog/tpm2.o
+tpm-y += tpm-buf.o
+tpm-y += tpm2-sessions.o
+
+tpm-$(CONFIG_ACPI) += tpm_ppi.o eventlog/acpi.o
+tpm-$(CONFIG_EFI) += eventlog/efi.o
+tpm-$(CONFIG_OF) += eventlog/of.o
+obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
+obj-$(CONFIG_TCG_TIS) += tpm_tis.o
+obj-$(CONFIG_TCG_TIS_SYNQUACER) += tpm_tis_synquacer.o
+
+obj-$(CONFIG_TCG_TIS_SPI) += tpm_tis_spi.o
+tpm_tis_spi-y := tpm_tis_spi_main.o
+tpm_tis_spi-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o
+
+obj-$(CONFIG_TCG_TIS_I2C_CR50) += tpm_tis_i2c_cr50.o
+
+obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o
+obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
+obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
+obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
+obj-$(CONFIG_TCG_NSC) += tpm_nsc.o
+obj-$(CONFIG_TCG_ATMEL) += tpm_atmel.o
+obj-$(CONFIG_TCG_INFINEON) += tpm_infineon.o
+obj-$(CONFIG_TCG_IBMVTPM) += tpm_ibmvtpm.o
+obj-$(CONFIG_TCG_TIS_ST33ZP24) += st33zp24/
+obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o
+obj-$(CONFIG_TCG_CRB) += tpm_crb.o
+obj-$(CONFIG_TCG_ARM_CRB_FFA) += tpm_crb_ffa.o
+obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o
+obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o
+obj-$(CONFIG_TCG_SVSM) += tpm_svsm.o
+obj-$(CONFIG_TCG_LOONGSON) += tpm_loongson.o