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, 92 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/trace.h b/drivers/usb/chipidea/trace.h
new file mode 100644
index 000000000..1875419cd
--- /dev/null
+++ b/drivers/usb/chipidea/trace.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Trace support header file for device mode
+ *
+ * Copyright (C) 2020 NXP
+ *
+ * Author: Peter Chen <peter.chen@nxp.com>
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM chipidea
+
+#if !defined(__LINUX_CHIPIDEA_TRACE) || defined(TRACE_HEADER_MULTI_READ)
+#define __LINUX_CHIPIDEA_TRACE
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+#include <linux/usb/chipidea.h>
+#include "ci.h"
+#include "udc.h"
+
+#define CHIPIDEA_MSG_MAX	500
+
+void ci_log(struct ci_hdrc *ci, const char *fmt, ...);
+
+TRACE_EVENT(ci_log,
+	TP_PROTO(struct ci_hdrc *ci, struct va_format *vaf),
+	TP_ARGS(ci, vaf),
+	TP_STRUCT__entry(
+		__string(name, dev_name(ci->dev))
+		__vstring(msg, vaf->fmt, vaf->va)
+	),
+	TP_fast_assign(
+		__assign_str(name);
+		__assign_vstr(msg, vaf->fmt, vaf->va);
+	),
+	TP_printk("%s: %s", __get_str(name), __get_str(msg))
+);
+
+DECLARE_EVENT_CLASS(ci_log_trb,
+	TP_PROTO(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq, struct td_node *td),
+	TP_ARGS(hwep, hwreq, td),
+	TP_STRUCT__entry(
+		__string(name, hwep->name)
+		__field(struct td_node *, td)
+		__field(struct usb_request *, req)
+		__field(dma_addr_t, dma)
+		__field(s32, td_remaining_size)
+		__field(u32, next)
+		__field(u32, token)
+		__field(u32, type)
+	),
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->req = &hwreq->req;
+		__entry->td = td;
+		__entry->dma = td->dma;
+		__entry->td_remaining_size = td->td_remaining_size;
+		__entry->next = le32_to_cpu(td->ptr->next);
+		__entry->token = le32_to_cpu(td->ptr->token);
+		__entry->type = usb_endpoint_type(hwep->ep.desc);
+	),
+	TP_printk("%s: req: %p, td: %p, td_dma_address: %pad, remaining_size: %d, "
+	       "next: %x, total bytes: %d, status: %lx",
+		__get_str(name), __entry->req, __entry->td, &__entry->dma,
+		__entry->td_remaining_size, __entry->next,
+		(int)((__entry->token & TD_TOTAL_BYTES) >> __ffs(TD_TOTAL_BYTES)),
+		__entry->token & TD_STATUS
+	)
+);
+
+DEFINE_EVENT(ci_log_trb, ci_prepare_td,
+	TP_PROTO(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq, struct td_node *td),
+	TP_ARGS(hwep, hwreq, td)
+);
+
+DEFINE_EVENT(ci_log_trb, ci_complete_td,
+	TP_PROTO(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq, struct td_node *td),
+	TP_ARGS(hwep, hwreq, td)
+);
+
+#endif /* __LINUX_CHIPIDEA_TRACE */
+
+/* this part must be outside header guard */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>