From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() 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 Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- arch/x86/kernel/amd_node.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/amd_node.c b/arch/x86/kernel/amd_node.c index 762585775b5a..b7926ba3610a 100644 --- a/arch/x86/kernel/amd_node.c +++ b/arch/x86/kernel/amd_node.c @@ -251,7 +251,7 @@ __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; @@ -262,7 +262,6 @@ 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"); @@ -299,14 +298,13 @@ static int __init amd_smn_init(void) count = 0; node = 0; - root = NULL; while (node < num_nodes && (root = get_next_root(root))) { /* Use one root for each node and skip the rest. */ if (count++ % roots_per_node) 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) { -- cgit v1.2.3