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, 106 insertions, 0 deletions

diff --git a/drivers/of/unittest-data/Makefile b/drivers/of/unittest-data/Makefile
new file mode 100644
index 000000000..01a966e39
--- /dev/null
+++ b/drivers/of/unittest-data/Makefile
@@ -0,0 +1,106 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y += testcases.dtbo.o
+
+obj-$(CONFIG_OF_OVERLAY) += overlay.dtbo.o \
+			    overlay_0.dtbo.o \
+			    overlay_1.dtbo.o \
+			    overlay_2.dtbo.o \
+			    overlay_3.dtbo.o \
+			    overlay_4.dtbo.o \
+			    overlay_5.dtbo.o \
+			    overlay_6.dtbo.o \
+			    overlay_7.dtbo.o \
+			    overlay_8.dtbo.o \
+			    overlay_9.dtbo.o \
+			    overlay_10.dtbo.o \
+			    overlay_11.dtbo.o \
+			    overlay_12.dtbo.o \
+			    overlay_13.dtbo.o \
+			    overlay_15.dtbo.o \
+			    overlay_16.dtbo.o \
+			    overlay_17.dtbo.o \
+			    overlay_18.dtbo.o \
+			    overlay_19.dtbo.o \
+			    overlay_20.dtbo.o \
+			    overlay_bad_add_dup_node.dtbo.o \
+			    overlay_bad_add_dup_prop.dtbo.o \
+			    overlay_bad_phandle.dtbo.o \
+			    overlay_bad_symbol.dtbo.o \
+			    overlay_base.dtbo.o \
+			    overlay_gpio_01.dtbo.o \
+			    overlay_gpio_02a.dtbo.o \
+			    overlay_gpio_02b.dtbo.o \
+			    overlay_gpio_03.dtbo.o \
+			    overlay_gpio_04a.dtbo.o \
+			    overlay_gpio_04b.dtbo.o \
+			    overlay_pci_node.dtbo.o \
+			    overlay_bad_unresolved.dtbo.o
+
+# enable creation of __symbols__ node
+DTC_FLAGS_overlay += -@
+DTC_FLAGS_overlay_bad_phandle += -@
+DTC_FLAGS_overlay_bad_symbol += -@
+DTC_FLAGS_overlay_base += -@
+DTC_FLAGS_testcases += -@
+
+# suppress warnings about intentional errors
+DTC_FLAGS_testcases += -Wno-interrupts_property \
+	-Wno-node_name_vs_property_name \
+	-Wno-interrupt_map
+
+# Apply overlays statically with fdtoverlay.  This is a build time test that
+# the overlays can be applied successfully by fdtoverlay.  This does not
+# guarantee that the overlays can be applied successfully at run time by
+# unittest, but it provides a bit of build time test coverage for those
+# who do not execute unittest.
+#
+# The overlays are applied on top of static_base_1.dtb and static_base_2.dtb to
+# create static_test_1.dtb and static_test_2.dtb.  If fdtoverlay detects an
+# error than the kernel build will fail.  static_test_1.dtb and
+# static_test_2.dtb are not consumed by unittest.
+#
+# Some unittest overlays deliberately contain errors that unittest checks for.
+# These overlays will cause fdtoverlay to fail, and are thus not included
+# in the static test:
+#			  overlay_bad_add_dup_node.dtbo \
+#			  overlay_bad_add_dup_prop.dtbo \
+#			  overlay_bad_phandle.dtbo \
+#			  overlay_bad_symbol.dtbo \
+
+apply_static_overlay_1 := overlay_0.dtbo \
+			  overlay_1.dtbo \
+			  overlay_2.dtbo \
+			  overlay_3.dtbo \
+			  overlay_4.dtbo \
+			  overlay_5.dtbo \
+			  overlay_6.dtbo \
+			  overlay_7.dtbo \
+			  overlay_8.dtbo \
+			  overlay_9.dtbo \
+			  overlay_10.dtbo \
+			  overlay_11.dtbo \
+			  overlay_12.dtbo \
+			  overlay_13.dtbo \
+			  overlay_15.dtbo \
+			  overlay_16.dtbo \
+			  overlay_17.dtbo \
+			  overlay_18.dtbo \
+			  overlay_19.dtbo \
+			  overlay_20.dtbo \
+			  overlay_gpio_01.dtbo \
+			  overlay_gpio_02a.dtbo \
+			  overlay_gpio_02b.dtbo \
+			  overlay_gpio_03.dtbo \
+			  overlay_gpio_04a.dtbo \
+			  overlay_gpio_04b.dtbo
+
+apply_static_overlay_2 := overlay.dtbo
+
+DTC_FLAGS_static_base_1 += -Wno-interrupts_property \
+	-Wno-node_name_vs_property_name \
+	-Wno-interrupt_map
+
+static_test_1-dtbs := static_base_1.dtb $(apply_static_overlay_1)
+static_test_2-dtbs := static_base_2.dtb $(apply_static_overlay_2)
+
+dtb-$(CONFIG_OF_OVERLAY) += static_test_1.dtb static_test_2.dtb