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, 256 insertions, 0 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
new file mode 100644
index 000000000..f2bed2dde
--- /dev/null
+++ b/drivers/Kconfig
@@ -0,0 +1,256 @@
+# SPDX-License-Identifier: GPL-2.0
+menu "Device Drivers"
+
+# Keep I/O buses first
+
+source "drivers/amba/Kconfig"
+source "drivers/eisa/Kconfig"
+source "drivers/pci/Kconfig"
+source "drivers/cxl/Kconfig"
+source "drivers/pcmcia/Kconfig"
+source "drivers/rapidio/Kconfig"
+
+config PC104
+	bool "PC/104 support" if EXPERT
+	help
+	  Expose PC/104 form factor device drivers and options available for
+	  selection and configuration. Enable this option if your target
+	  machine has a PC/104 bus.
+
+source "drivers/base/Kconfig"
+
+source "drivers/bus/Kconfig"
+
+source "drivers/cache/Kconfig"
+
+source "drivers/connector/Kconfig"
+
+source "drivers/firmware/Kconfig"
+
+source "drivers/fwctl/Kconfig"
+
+source "drivers/gnss/Kconfig"
+
+source "drivers/mtd/Kconfig"
+
+source "drivers/of/Kconfig"
+
+source "drivers/parport/Kconfig"
+
+source "drivers/pnp/Kconfig"
+
+source "drivers/block/Kconfig"
+
+source "drivers/nvme/Kconfig"
+
+source "drivers/misc/Kconfig"
+
+source "drivers/scsi/Kconfig"
+
+source "drivers/ata/Kconfig"
+
+source "drivers/md/Kconfig"
+
+source "drivers/target/Kconfig"
+
+source "drivers/message/fusion/Kconfig"
+
+source "drivers/firewire/Kconfig"
+
+source "drivers/macintosh/Kconfig"
+
+source "drivers/net/Kconfig"
+
+# input before char - char/joystick depends on it. As does USB.
+
+source "drivers/input/Kconfig"
+
+source "drivers/char/Kconfig"
+
+source "drivers/i2c/Kconfig"
+
+source "drivers/i3c/Kconfig"
+
+source "drivers/spi/Kconfig"
+
+source "drivers/spmi/Kconfig"
+
+source "drivers/hsi/Kconfig"
+
+source "drivers/pps/Kconfig"
+
+source "drivers/ptp/Kconfig"
+
+source "drivers/dpll/Kconfig"
+
+source "drivers/pinctrl/Kconfig"
+
+source "drivers/gpio/Kconfig"
+
+source "drivers/w1/Kconfig"
+
+source "drivers/power/Kconfig"
+
+source "drivers/hwmon/Kconfig"
+
+source "drivers/thermal/Kconfig"
+
+source "drivers/watchdog/Kconfig"
+
+source "drivers/ssb/Kconfig"
+
+source "drivers/bcma/Kconfig"
+
+source "drivers/mfd/Kconfig"
+
+source "drivers/regulator/Kconfig"
+
+source "drivers/media/Kconfig"
+
+source "drivers/video/Kconfig"
+
+source "drivers/accel/Kconfig"
+
+source "sound/Kconfig"
+
+source "drivers/hid/Kconfig"
+
+source "drivers/usb/Kconfig"
+
+source "drivers/mmc/Kconfig"
+
+source "drivers/ufs/Kconfig"
+
+source "drivers/memstick/Kconfig"
+
+source "drivers/leds/Kconfig"
+
+source "drivers/accessibility/Kconfig"
+
+source "drivers/infiniband/Kconfig"
+
+source "drivers/edac/Kconfig"
+
+source "drivers/rtc/Kconfig"
+
+source "drivers/dma/Kconfig"
+
+source "drivers/dma-buf/Kconfig"
+
+source "drivers/dca/Kconfig"
+
+source "drivers/uio/Kconfig"
+
+source "drivers/vfio/Kconfig"
+
+source "drivers/virt/Kconfig"
+
+source "drivers/virtio/Kconfig"
+
+source "drivers/vdpa/Kconfig"
+
+source "drivers/vhost/Kconfig"
+
+source "drivers/hv/Kconfig"
+
+source "drivers/xen/Kconfig"
+
+source "drivers/greybus/Kconfig"
+
+source "drivers/comedi/Kconfig"
+
+source "drivers/gpib/Kconfig"
+
+source "drivers/staging/Kconfig"
+
+source "drivers/platform/Kconfig"
+
+source "drivers/clk/Kconfig"
+
+source "drivers/hwspinlock/Kconfig"
+
+source "drivers/clocksource/Kconfig"
+
+source "drivers/mailbox/Kconfig"
+
+source "drivers/iommu/Kconfig"
+
+source "drivers/remoteproc/Kconfig"
+
+source "drivers/rpmsg/Kconfig"
+
+source "drivers/soundwire/Kconfig"
+
+source "drivers/soc/Kconfig"
+
+source "drivers/pmdomain/Kconfig"
+
+source "drivers/devfreq/Kconfig"
+
+source "drivers/extcon/Kconfig"
+
+source "drivers/memory/Kconfig"
+
+source "drivers/iio/Kconfig"
+
+source "drivers/ntb/Kconfig"
+
+source "drivers/pwm/Kconfig"
+
+source "drivers/irqchip/Kconfig"
+
+source "drivers/ipack/Kconfig"
+
+source "drivers/reset/Kconfig"
+
+source "drivers/phy/Kconfig"
+
+source "drivers/powercap/Kconfig"
+
+source "drivers/mcb/Kconfig"
+
+source "drivers/perf/Kconfig"
+
+source "drivers/ras/Kconfig"
+
+source "drivers/thunderbolt/Kconfig"
+
+source "drivers/android/Kconfig"
+
+source "drivers/nvdimm/Kconfig"
+
+source "drivers/dax/Kconfig"
+
+source "drivers/nvmem/Kconfig"
+
+source "drivers/hwtracing/Kconfig"
+
+source "drivers/fpga/Kconfig"
+
+source "drivers/fsi/Kconfig"
+
+source "drivers/tee/Kconfig"
+
+source "drivers/mux/Kconfig"
+
+source "drivers/opp/Kconfig"
+
+source "drivers/siox/Kconfig"
+
+source "drivers/slimbus/Kconfig"
+
+source "drivers/interconnect/Kconfig"
+
+source "drivers/counter/Kconfig"
+
+source "drivers/most/Kconfig"
+
+source "drivers/peci/Kconfig"
+
+source "drivers/hte/Kconfig"
+
+source "drivers/cdx/Kconfig"
+
+source "drivers/resctrl/Kconfig"
+
+endmenu