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, 80 insertions, 0 deletions

diff --git a/scripts/dtc/update-dtc-source.sh b/scripts/dtc/update-dtc-source.sh
new file mode 100755
index 000000000..946275415
--- /dev/null
+++ b/scripts/dtc/update-dtc-source.sh
@@ -0,0 +1,80 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Simple script to update the version of DTC carried by the Linux kernel
+#
+# This script assumes that the dtc and the linux git trees are in the
+# same directory. After building dtc in the dtc directory, it copies the
+# source files and generated source file(s) into the scripts/dtc directory
+# in the kernel and creates a git commit updating them to the new
+# version.
+#
+# Usage: from the top level Linux source tree, run:
+# $ ./scripts/dtc/update-dtc-source.sh
+#
+# The script will change into the dtc tree, build and test dtc, copy the
+# relevant files into the kernel tree and create a git commit. The commit
+# message will need to be modified to reflect the version of DTC being
+# imported
+#
+# TODO:
+# This script is pretty basic, but it is seldom used so a few manual tasks
+# aren't a big deal. If anyone is interested in making it more robust, the
+# the following would be nice:
+# * Actually fail to complete if any testcase fails.
+#   - The dtc "make check" target needs to return a failure
+# * Extract the version number from the dtc repo for the commit message
+# * Build dtc in the kernel tree
+# * run 'make check" on dtc built from the kernel tree
+
+set -ev
+
+DTC_UPSTREAM_PATH=`pwd`/../dtc
+DTC_LINUX_PATH=`pwd`/scripts/dtc
+
+DTC_SOURCE="checks.c data.c dtc.c dtc.h flattree.c fstree.c livetree.c srcpos.c \
+		srcpos.h treesource.c util.c util.h version_gen.h \
+		dtc-lexer.l dtc-parser.y"
+LIBFDT_SOURCE="fdt.c fdt.h fdt_addresses.c fdt_empty_tree.c \
+		fdt_overlay.c fdt_ro.c fdt_rw.c fdt_strerror.c fdt_sw.c \
+		fdt_wip.c libfdt.h libfdt_env.h libfdt_internal.h"
+FDTOVERLAY_SOURCE=fdtoverlay.c
+
+get_last_dtc_version() {
+	git log --oneline scripts/dtc/ | grep 'upstream' | head -1 | sed -e 's/^.* \(.*\)/\1/'
+}
+
+last_dtc_ver=$(get_last_dtc_version)
+
+# Build DTC
+cd $DTC_UPSTREAM_PATH
+make clean
+make check
+dtc_version=$(git describe HEAD)
+dtc_log=$(git log --oneline ${last_dtc_ver}..)
+
+
+# Copy the files into the Linux tree
+cd $DTC_LINUX_PATH
+for f in $DTC_SOURCE $FDTOVERLAY_SOURCE; do
+	cp ${DTC_UPSTREAM_PATH}/${f} ${f}
+	git add ${f}
+done
+for f in $LIBFDT_SOURCE; do
+       cp ${DTC_UPSTREAM_PATH}/libfdt/${f} libfdt/${f}
+       git add libfdt/${f}
+done
+
+sed -i -- 's/#include <libfdt_env.h>/#include "libfdt_env.h"/g' ./libfdt/libfdt.h
+sed -i -- 's/#include <fdt.h>/#include "fdt.h"/g' ./libfdt/libfdt.h
+git add ./libfdt/libfdt.h
+
+commit_msg=$(cat << EOF
+scripts/dtc: Update to upstream version ${dtc_version}
+
+This adds the following commits from upstream:
+
+${dtc_log}
+EOF
+)
+
+git commit -e -v -s -m "${commit_msg}"