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, 63 insertions, 0 deletions

diff --git a/scripts/module.lds.S b/scripts/module.lds.S
new file mode 100644
index 000000000..d0f200428
--- /dev/null
+++ b/scripts/module.lds.S
@@ -0,0 +1,63 @@
+/*
+ * Common module linker script, always used when linking a module.
+ * Archs are free to supply their own linker scripts.  ld will
+ * combine them automatically.
+ */
+
+#include <asm-generic/codetag.lds.h>
+
+SECTIONS {
+	/DISCARD/ : {
+		*(.discard)
+		*(.discard.*)
+		*(.export_symbol)
+		*(.no_trim_symbol)
+	}
+
+	__ksymtab		0 : ALIGN(8) { *(SORT(___ksymtab+*)) }
+	__kcrctab		0 : ALIGN(4) { *(SORT(___kcrctab+*)) }
+	__kflagstab		0 : ALIGN(1) { *(SORT(___kflagstab+*)) }
+
+	.ctors			0 : ALIGN(8) { *(SORT(.ctors.*)) *(.ctors) }
+	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
+
+	.altinstructions	0 : ALIGN(8) { KEEP(*(.altinstructions)) }
+	__bug_table		0 : ALIGN(8) { KEEP(*(__bug_table)) }
+	__jump_table		0 : ALIGN(8) { KEEP(*(__jump_table)) }
+	__ex_table		0 : ALIGN(4) { KEEP(*(__ex_table)) }
+
+	__patchable_function_entries 0 : { *(__patchable_function_entries) }
+
+	.init.klp_funcs		0 : ALIGN(8) { KEEP(*(.init.klp_funcs)) }
+	.init.klp_objects	0 : ALIGN(8) { KEEP(*(.init.klp_objects)) }
+
+#ifdef CONFIG_ARCH_USES_CFI_TRAPS
+	__kcfi_traps		0 : { KEEP(*(.kcfi_traps)) }
+#endif
+
+#ifndef CONFIG_ARCH_WANTS_MODULES_TEXT_SECTIONS
+	.text			0 : {
+		*(.text .text.[0-9a-zA-Z_]*)
+	}
+#endif
+
+	.bss			0 : {
+		*(.bss .bss.[0-9a-zA-Z_]*)
+		*(.bss..L*)
+	}
+
+	.data			0 : {
+		*(.data .data.[0-9a-zA-Z_]*)
+		*(.data..L*)
+	}
+
+	.rodata			0 : {
+		*(.rodata .rodata.[0-9a-zA-Z_]*)
+		*(.rodata..L*)
+	}
+
+	MOD_SEPARATE_CODETAG_SECTIONS()
+}
+
+/* bring in arch-specific sections */
+#include <asm/module.lds.h>