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, 107 insertions, 0 deletions

diff --git a/include/trace/events/iscsi.h b/include/trace/events/iscsi.h
new file mode 100644
index 000000000..990fd154f
--- /dev/null
+++ b/include/trace/events/iscsi.h
@@ -0,0 +1,107 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM iscsi
+
+#if !defined(_TRACE_ISCSI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ISCSI_H
+
+#include <linux/tracepoint.h>
+
+/* max debug message length */
+#define ISCSI_MSG_MAX	256
+
+/*
+ * Declare tracepoint helper function.
+ */
+void iscsi_dbg_trace(void (*trace)(struct device *dev, struct va_format *),
+		     struct device *dev, const char *fmt, ...);
+
+/*
+ * Declare event class for iscsi debug messages.
+ */
+DECLARE_EVENT_CLASS(iscsi_log_msg,
+
+	TP_PROTO(struct device *dev, struct va_format *vaf),
+
+	TP_ARGS(dev, vaf),
+
+	TP_STRUCT__entry(
+		__string(dname, 	dev_name(dev)		)
+		__vstring(msg,		vaf->fmt, vaf->va)
+	),
+
+	TP_fast_assign(
+		__assign_str(dname);
+		__assign_vstr(msg, vaf->fmt, vaf->va);
+	),
+
+	TP_printk("%s: %s",__get_str(dname),  __get_str(msg)
+	)
+);
+
+/*
+ * Define event to capture iscsi connection debug messages.
+ */
+DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_conn,
+	TP_PROTO(struct device *dev, struct va_format *vaf),
+
+	TP_ARGS(dev, vaf)
+);
+
+/*
+ * Define event to capture iscsi session debug messages.
+ */
+DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_session,
+	TP_PROTO(struct device *dev, struct va_format *vaf),
+
+	TP_ARGS(dev, vaf)
+);
+
+/*
+ * Define event to capture iscsi error handling debug messages.
+ */
+DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_eh,
+        TP_PROTO(struct device *dev, struct va_format *vaf),
+
+        TP_ARGS(dev, vaf)
+);
+
+/*
+ * Define event to capture iscsi tcp debug messages.
+ */
+DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_tcp,
+        TP_PROTO(struct device *dev, struct va_format *vaf),
+
+        TP_ARGS(dev, vaf)
+);
+
+/*
+ * Define event to capture iscsi sw tcp debug messages.
+ */
+DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_sw_tcp,
+	TP_PROTO(struct device *dev, struct va_format *vaf),
+
+	TP_ARGS(dev, vaf)
+);
+
+/*
+ * Define event to capture iscsi transport session debug messages.
+ */
+DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_trans_session,
+	TP_PROTO(struct device *dev, struct va_format *vaf),
+
+	TP_ARGS(dev, vaf)
+);
+
+/*
+ * Define event to capture iscsi transport connection debug messages.
+ */
+DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_trans_conn,
+	TP_PROTO(struct device *dev, struct va_format *vaf),
+
+	TP_ARGS(dev, vaf)
+);
+
+#endif /* _TRACE_ISCSI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>