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, 55 insertions, 0 deletions

diff --git a/drivers/sh/intc/virq-debugfs.c b/drivers/sh/intc/virq-debugfs.c
new file mode 100644
index 000000000..5dd8febe6
--- /dev/null
+++ b/drivers/sh/intc/virq-debugfs.c
@@ -0,0 +1,55 @@
+/*
+ * Support for virtual IRQ subgroups debugfs mapping.
+ *
+ * Copyright (C) 2010  Paul Mundt
+ *
+ * Modelled after arch/powerpc/kernel/irq.c.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/debugfs.h>
+#include "internals.h"
+
+static int intc_irq_xlate_show(struct seq_file *m, void *priv)
+{
+	const unsigned int nr_irqs = irq_get_nr_irqs();
+	int i;
+
+	seq_printf(m, "%-5s  %-7s  %-15s\n", "irq", "enum", "chip name");
+
+	for (i = 1; i < nr_irqs; i++) {
+		struct intc_map_entry *entry = intc_irq_xlate_get(i);
+		struct intc_desc_int *desc = entry->desc;
+
+		if (!desc)
+			continue;
+
+		seq_printf(m, "%5d  ", i);
+		seq_printf(m, "0x%05x  ", entry->enum_id);
+		seq_printf(m, "%-15s\n", desc->chip.name);
+	}
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(intc_irq_xlate);
+
+static int __init intc_irq_xlate_init(void)
+{
+	/*
+	 * XXX.. use arch_debugfs_dir here when all of the intc users are
+	 * converted.
+	 */
+	if (debugfs_create_file("intc_irq_xlate", S_IRUGO, NULL, NULL,
+				&intc_irq_xlate_fops) == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+fs_initcall(intc_irq_xlate_init);