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, 32 insertions, 0 deletions

diff --git a/scripts/makelst b/scripts/makelst
new file mode 100755
index 000000000..e432af073
--- /dev/null
+++ b/scripts/makelst
@@ -0,0 +1,32 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# A script to dump mixed source code & assembly
+# with correct relocations from System.map
+# Requires the following lines in makefile:
+#%.lst: %.c
+#	$(CC) $(c_flags) -g -c -o $*.o $< &&
+#	$(srctree)/scripts/makelst $*.o System.map $(OBJDUMP) > $@
+#
+# Copyright (C) 2000 IBM Corporation
+# Author(s): DJ Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
+#            William Stearns <wstearns@pobox.com>
+#
+
+# awk style field access
+field() {
+  shift $1 ; echo $1
+}
+
+t1=`$3 --syms $1 | grep .text | grep -m1 " F "`
+if [ -n "$t1" ]; then
+  t2=`field 6 $t1`
+  if [ ! -r $2 ]; then
+    echo "No System.map" >&2
+  else
+    t3=`grep $t2 $2`
+    t4=`field 1 $t3`
+    t5=`field 1 $t1`
+    t6=`printf "%lu" $((0x$t4 - 0x$t5))`
+  fi
+fi
+$3 -r --source --adjust-vma=${t6:-0} $1