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, 27 insertions, 0 deletions

diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
new file mode 100644
index 000000000..b47f4daa4
--- /dev/null
+++ b/scripts/dtc/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+# scripts/dtc makefile
+
+# *** Also keep .gitignore in sync when changing ***
+hostprogs-always-$(CONFIG_DTC)		+= dtc fdtoverlay
+hostprogs-always-$(CHECK_DTBS)		+= dtc
+
+dtc-objs	:= dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
+		   srcpos.o checks.o util.o
+dtc-objs	+= dtc-lexer.lex.o dtc-parser.tab.o
+
+# The upstream project builds libfdt as a separate library.  We are choosing to
+# instead directly link the libfdt object files into fdtoverlay.
+libfdt-objs	:= fdt.o fdt_ro.o fdt_wip.o fdt_sw.o fdt_rw.o fdt_strerror.o fdt_empty_tree.o fdt_addresses.o fdt_overlay.o
+libfdt		= $(addprefix libfdt/,$(libfdt-objs))
+fdtoverlay-objs	:= $(libfdt) fdtoverlay.o util.o
+
+# Source files need to get at the userspace version of libfdt_env.h to compile
+HOST_EXTRACFLAGS += -I $(src)/libfdt
+HOST_EXTRACFLAGS += -DNO_YAML
+
+# Generated files need one more search path to include headers in source tree
+HOSTCFLAGS_dtc-lexer.lex.o := -I $(src)
+HOSTCFLAGS_dtc-parser.tab.o := -I $(src)
+
+# dependencies on generated files need to be listed explicitly
+$(obj)/dtc-lexer.lex.o: $(obj)/dtc-parser.tab.h