[PATCH] x86/amd_node: Fix PCI device reference counting in amd_smn_init()

[Yazen Ghannam]

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.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Assisted-by: Claude-Code:claude-opus-5
Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
---
 arch/x86/kernel/amd_node.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/amd_node.c b/arch/x86/kernel/amd_node.c
index 0be01725a2a4..312adf73313b 100644
--- a/arch/x86/kernel/amd_node.c
+++ b/arch/x86/kernel/amd_node.c
@@ -247,7 +247,7 @@ __setup("amd_smn_debugfs_enable", amd_smn_enable_dfs);
 static int __init amd_smn_init(void)
 {
 	u16 count, num_roots, roots_per_node, node, num_nodes;
-	struct pci_dev *root;
+	struct pci_dev *root __free(pci_dev_put) = NULL;
 
 	if (!cpu_feature_enabled(X86_FEATURE_ZEN))
 		return 0;
@@ -258,7 +258,6 @@ static int __init amd_smn_init(void)
 		return 0;
 
 	num_roots = 0;
-	root = NULL;
 	while ((root = get_next_root(root))) {
 		pci_dbg(root, "Reserving PCI config space\n");
 
@@ -297,7 +296,7 @@ static int __init amd_smn_init(void)
 			continue;
 
 		pci_dbg(root, "is root for AMD node %u\n", node);
-		amd_roots[node++] = root;
+		amd_roots[node++] = pci_dev_get(root);
 	}
 
 	if (enable_dfs) {

base-commit: 8d3ae59288f1e7d58d76558a6ee96d533bc5019f
-- 
2.43.0