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, 33 insertions, 0 deletions

diff --git a/tools/testing/ktest/compare-ktest-sample.pl b/tools/testing/ktest/compare-ktest-sample.pl
new file mode 100755
index 000000000..ebea21d0a
--- /dev/null
+++ b/tools/testing/ktest/compare-ktest-sample.pl
@@ -0,0 +1,33 @@
+#!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+
+open (IN,"ktest.pl");
+while (<IN>) {
+    # hashes are now used
+    if (/\$opt\{"?([A-Z].*?)(\[.*\])?"?\}/ ||
+	/^\s*"?([A-Z].*?)"?\s*=>\s*/ ||
+	/set_test_option\("(.*?)"/) {
+	$opt{$1} = 1;
+    }
+}
+close IN;
+
+open (IN, "sample.conf");
+while (<IN>) {
+    if (/^\s*#?\s*([A-Z]\S*)\s*=/) {
+	$samp{$1} = 1;
+    }
+}
+close IN;
+
+foreach $opt (keys %opt) {
+    if (!defined($samp{$opt})) {
+	print "opt = $opt\n";
+    }
+}
+
+foreach $samp (keys %samp) {
+    if (!defined($opt{$samp})) {
+	print "samp = $samp\n";
+    }
+}