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, 214 insertions, 0 deletions

diff --git a/tools/docs/get_abi.py b/tools/docs/get_abi.py
new file mode 100755
index 000000000..2f0b99401
--- /dev/null
+++ b/tools/docs/get_abi.py
@@ -0,0 +1,214 @@
+#!/usr/bin/env python3
+# pylint: disable=R0903
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Parse ABI documentation and produce results from it.
+"""
+
+import argparse
+import logging
+import os
+import sys
+
+# Import Python modules
+
+LIB_DIR = "../lib/python"
+SRC_DIR = os.path.dirname(os.path.realpath(__file__))
+
+sys.path.insert(0, os.path.join(SRC_DIR, LIB_DIR))
+
+from abi.abi_parser import AbiParser                # pylint: disable=C0413
+from abi.abi_regex import AbiRegex                  # pylint: disable=C0413
+from abi.helpers import ABI_DIR, DEBUG_HELP         # pylint: disable=C0413
+from abi.system_symbols import SystemSymbols        # pylint: disable=C0413
+
+# Command line classes
+
+
+REST_DESC = """
+Produce output in ReST format.
+
+The output is done on two sections:
+
+- Symbols: show all parsed symbols in alphabetic order;
+- Files: cross reference the content of each file with the symbols on it.
+"""
+
+class AbiRest:
+    """Initialize an argparse subparser for rest output"""
+
+    def __init__(self, subparsers):
+        """Initialize argparse subparsers"""
+
+        parser = subparsers.add_parser("rest",
+                                       formatter_class=argparse.RawTextHelpFormatter,
+                                       description=REST_DESC)
+
+        parser.add_argument("--enable-lineno",  action="store_true",
+                            help="enable lineno")
+        parser.add_argument("--raw", action="store_true",
+                            help="output text as contained in the ABI files. "
+                                 "It not used, output will contain dynamically"
+                                 " generated cross references when possible.")
+        parser.add_argument("--no-file", action="store_true",
+                            help="Don't the files section")
+        parser.add_argument("--show-hints", help="Show-hints")
+
+        parser.set_defaults(func=self.run)
+
+    def run(self, args):
+        """Run subparser"""
+
+        parser = AbiParser(args.dir, debug=args.debug)
+        parser.parse_abi()
+        parser.check_issues()
+
+        for t in parser.doc(args.raw, not args.no_file):
+            if args.enable_lineno:
+                print (f".. LINENO {t[1]}#{t[2]}\n\n")
+
+            print(t[0])
+
+class AbiValidate:
+    """Initialize an argparse subparser for ABI validation"""
+
+    def __init__(self, subparsers):
+        """Initialize argparse subparsers"""
+
+        parser = subparsers.add_parser("validate",
+                                       formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+                                       description="list events")
+
+        parser.set_defaults(func=self.run)
+
+    def run(self, args):
+        """Run subparser"""
+
+        parser = AbiParser(args.dir, debug=args.debug)
+        parser.parse_abi()
+        parser.check_issues()
+
+
+class AbiSearch:
+    """Initialize an argparse subparser for ABI search"""
+
+    def __init__(self, subparsers):
+        """Initialize argparse subparsers"""
+
+        parser = subparsers.add_parser("search",
+                                       formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+                                       description="Search ABI using a regular expression")
+
+        parser.add_argument("expression",
+                            help="Case-insensitive search pattern for the ABI symbol")
+
+        parser.set_defaults(func=self.run)
+
+    def run(self, args):
+        """Run subparser"""
+
+        parser = AbiParser(args.dir, debug=args.debug)
+        parser.parse_abi()
+        parser.search_symbols(args.expression)
+
+UNDEFINED_DESC="""
+Check undefined ABIs on local machine.
+
+Read sysfs devnodes and check if the devnodes there are defined inside
+ABI documentation.
+
+The search logic tries to minimize the number of regular expressions to
+search per each symbol.
+
+By default, it runs on a single CPU, as Python support for CPU threads
+is still experimental, and multi-process runs on Python is very slow.
+
+On experimental tests, if the number of ABI symbols to search per devnode
+is contained on a limit of ~150 regular expressions, using a single CPU
+is a lot faster than using multiple processes. However, if the number of
+regular expressions to check is at the order of ~30000, using multiple
+CPUs speeds up the check.
+"""
+
+class AbiUndefined:
+    """
+    Initialize an argparse subparser for logic to check undefined ABI at
+    the current machine's sysfs
+    """
+
+    def __init__(self, subparsers):
+        """Initialize argparse subparsers"""
+
+        parser = subparsers.add_parser("undefined",
+                                       formatter_class=argparse.RawTextHelpFormatter,
+                                       description=UNDEFINED_DESC)
+
+        parser.add_argument("-S", "--sysfs-dir", default="/sys",
+                            help="directory where sysfs is mounted")
+        parser.add_argument("-s", "--search-string",
+                            help="search string regular expression to limit symbol search")
+        parser.add_argument("-H", "--show-hints", action="store_true",
+                            help="Hints about definitions for missing ABI symbols.")
+        parser.add_argument("-j", "--jobs", "--max-workers", type=int, default=1,
+                            help="If bigger than one, enables multiprocessing.")
+        parser.add_argument("-c", "--max-chunk-size", type=int, default=50,
+                            help="Maximum number of chunk size")
+        parser.add_argument("-f", "--found", action="store_true",
+                            help="Also show found items. "
+                                 "Helpful to debug the parser."),
+        parser.add_argument("-d", "--dry-run", action="store_true",
+                            help="Don't actually search for undefined. "
+                                 "Helpful to debug the parser."),
+
+        parser.set_defaults(func=self.run)
+
+    def run(self, args):
+        """Run subparser"""
+
+        abi = AbiRegex(args.dir, debug=args.debug,
+                       search_string=args.search_string)
+
+        abi_symbols = SystemSymbols(abi=abi, hints=args.show_hints,
+                                    sysfs=args.sysfs_dir)
+
+        abi_symbols.check_undefined_symbols(dry_run=args.dry_run,
+                                            found=args.found,
+                                            max_workers=args.jobs,
+                                            chunk_size=args.max_chunk_size)
+
+
+def main():
+    """Main program"""
+
+    parser = argparse.ArgumentParser(formatter_class=argparse.RawTextHelpFormatter)
+
+    parser.add_argument("-d", "--debug", type=int, default=0, help="debug level")
+    parser.add_argument("-D", "--dir", default=ABI_DIR, help=DEBUG_HELP)
+
+    subparsers = parser.add_subparsers()
+
+    AbiRest(subparsers)
+    AbiValidate(subparsers)
+    AbiSearch(subparsers)
+    AbiUndefined(subparsers)
+
+    args = parser.parse_args()
+
+    if args.debug:
+        level = logging.DEBUG
+    else:
+        level = logging.INFO
+
+    logging.basicConfig(level=level, format="[%(levelname)s] %(message)s")
+
+    if "func" in args:
+        args.func(args)
+    else:
+        sys.exit(f"Please specify a valid command for {sys.argv[0]}")
+
+
+# Call main method
+if __name__ == "__main__":
+    main()