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, 197 insertions, 0 deletions

diff --git a/drivers/thunderbolt/trace.h b/drivers/thunderbolt/trace.h
new file mode 100644
index 000000000..6d0776514
--- /dev/null
+++ b/drivers/thunderbolt/trace.h
@@ -0,0 +1,197 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Thunderbolt tracing support
+ *
+ * Copyright (C) 2024, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *	   Gil Fine <gil.fine@intel.com>
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM thunderbolt
+
+#if !defined(TB_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
+#define TB_TRACE_H_
+
+#include <linux/trace_seq.h>
+#include <linux/tracepoint.h>
+
+#include "tb_msgs.h"
+
+#define tb_cfg_type_name(type)		{ type, #type }
+#define show_type_name(val)					\
+	__print_symbolic(val,					\
+		tb_cfg_type_name(TB_CFG_PKG_READ),		\
+		tb_cfg_type_name(TB_CFG_PKG_WRITE),		\
+		tb_cfg_type_name(TB_CFG_PKG_ERROR),		\
+		tb_cfg_type_name(TB_CFG_PKG_NOTIFY_ACK),	\
+		tb_cfg_type_name(TB_CFG_PKG_EVENT),		\
+		tb_cfg_type_name(TB_CFG_PKG_XDOMAIN_REQ),	\
+		tb_cfg_type_name(TB_CFG_PKG_XDOMAIN_RESP),	\
+		tb_cfg_type_name(TB_CFG_PKG_OVERRIDE),		\
+		tb_cfg_type_name(TB_CFG_PKG_RESET),		\
+		tb_cfg_type_name(TB_CFG_PKG_ICM_EVENT),		\
+		tb_cfg_type_name(TB_CFG_PKG_ICM_CMD),		\
+		tb_cfg_type_name(TB_CFG_PKG_ICM_RESP))
+
+#ifndef TB_TRACE_HELPERS
+#define TB_TRACE_HELPERS
+static inline const char *show_data_read_write(struct trace_seq *p,
+					       const u32 *data)
+{
+	const struct cfg_read_pkg *msg = (const struct cfg_read_pkg *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "offset=%#x, len=%u, port=%d, config=%#x, seq=%d, ",
+			 msg->addr.offset, msg->addr.length, msg->addr.port,
+			 msg->addr.space, msg->addr.seq);
+
+	return ret;
+}
+
+static inline const char *show_data_error(struct trace_seq *p, const u32 *data)
+{
+	const struct cfg_error_pkg *msg = (const struct cfg_error_pkg *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "error=%#x, port=%d, plug=%#x, ", msg->error,
+			 msg->port, msg->pg);
+
+	return ret;
+}
+
+static inline const char *show_data_event(struct trace_seq *p, const u32 *data)
+{
+	const struct cfg_event_pkg *msg = (const struct cfg_event_pkg *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "port=%d, unplug=%#x, ", msg->port, msg->unplug);
+
+	return ret;
+}
+
+static inline const char *show_route(struct trace_seq *p, const u32 *data)
+{
+	const struct tb_cfg_header *header = (const struct tb_cfg_header *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "route=%llx, ", tb_cfg_get_route(header));
+
+	return ret;
+}
+
+static inline const char *show_data(struct trace_seq *p, u8 type,
+				    const u32 *data, u32 length)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+	const char *prefix = "";
+	int i;
+
+	switch (type) {
+	case TB_CFG_PKG_READ:
+	case TB_CFG_PKG_WRITE:
+		show_route(p, data);
+		show_data_read_write(p, data);
+		break;
+
+	case TB_CFG_PKG_ERROR:
+		show_route(p, data);
+		show_data_error(p, data);
+		break;
+
+	case TB_CFG_PKG_EVENT:
+		show_route(p, data);
+		show_data_event(p, data);
+		break;
+
+	case TB_CFG_PKG_ICM_EVENT:
+	case TB_CFG_PKG_ICM_CMD:
+	case TB_CFG_PKG_ICM_RESP:
+		/* ICM messages always target the host router */
+		trace_seq_puts(p, "route=0, ");
+		break;
+
+	default:
+		show_route(p, data);
+		break;
+	}
+
+	trace_seq_printf(p, "data=[");
+	for (i = 0; i < length; i++) {
+		trace_seq_printf(p, "%s0x%08x", prefix, data[i]);
+		prefix = ", ";
+	}
+	trace_seq_printf(p, "]");
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+#endif
+
+DECLARE_EVENT_CLASS(tb_raw,
+	TP_PROTO(int index, u8 type, const void *data, size_t size),
+	TP_ARGS(index, type, data, size),
+	TP_STRUCT__entry(
+		__field(int, index)
+		__field(u8, type)
+		__field(size_t, size)
+		__dynamic_array(u32, data, size / 4)
+	),
+	TP_fast_assign(
+		__entry->index = index;
+		__entry->type = type;
+		__entry->size = size / 4;
+		memcpy(__get_dynamic_array(data), data, size);
+	),
+	TP_printk("type=%s, size=%zd, domain=%d, %s",
+		  show_type_name(__entry->type), __entry->size, __entry->index,
+		  show_data(p, __entry->type, __get_dynamic_array(data),
+			    __entry->size)
+	)
+);
+
+DEFINE_EVENT(tb_raw, tb_tx,
+	TP_PROTO(int index, u8 type, const void *data, size_t size),
+	TP_ARGS(index, type, data, size)
+);
+
+DEFINE_EVENT(tb_raw, tb_event,
+	TP_PROTO(int index, u8 type, const void *data, size_t size),
+	TP_ARGS(index, type, data, size)
+);
+
+TRACE_EVENT(tb_rx,
+	TP_PROTO(int index, u8 type, const void *data, size_t size, bool dropped),
+	TP_ARGS(index, type, data, size, dropped),
+	TP_STRUCT__entry(
+		__field(int, index)
+		__field(u8, type)
+		__field(size_t, size)
+		__dynamic_array(u32, data, size / 4)
+		__field(bool, dropped)
+	),
+	TP_fast_assign(
+		__entry->index = index;
+		__entry->type = type;
+		__entry->size = size / 4;
+		memcpy(__get_dynamic_array(data), data, size);
+		__entry->dropped = dropped;
+	),
+	TP_printk("type=%s, dropped=%u, size=%zd, domain=%d, %s",
+		  show_type_name(__entry->type), __entry->dropped,
+		  __entry->size, __entry->index,
+		  show_data(p, __entry->type, __get_dynamic_array(data),
+			    __entry->size)
+	)
+);
+
+#endif /* TB_TRACE_H_ */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>