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, 115 insertions, 0 deletions

diff --git a/include/trace/events/amdxdna.h b/include/trace/events/amdxdna.h
new file mode 100644
index 000000000..71da24267
--- /dev/null
+++ b/include/trace/events/amdxdna.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023-2024, Advanced Micro Devices, Inc.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM amdxdna
+
+#if !defined(_TRACE_AMDXDNA_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_AMDXDNA_H
+
+#include <drm/gpu_scheduler.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(amdxdna_debug_point,
+	    TP_PROTO(const char *name, u64 number, const char *str),
+
+	    TP_ARGS(name, number, str),
+
+	    TP_STRUCT__entry(__string(name, name)
+			     __field(u64, number)
+			     __string(str, str)),
+
+	    TP_fast_assign(__assign_str(name);
+			   __entry->number = number;
+			   __assign_str(str);),
+
+	    TP_printk("%s:%llu %s", __get_str(name), __entry->number,
+		      __get_str(str))
+);
+
+TRACE_EVENT(xdna_job,
+	    TP_PROTO(struct drm_sched_job *sched_job, const char *name,
+		     const char *str, u64 seq, u32 op),
+
+	    TP_ARGS(sched_job, name, str, seq, op),
+
+	    TP_STRUCT__entry(__string(name, name)
+			     __string(str, str)
+			     __field(u64, fence_context)
+			     __field(u64, fence_seqno)
+			     __field(u64, seq)
+			     __field(u32, op)),
+
+	    TP_fast_assign(__assign_str(name);
+			   __assign_str(str);
+			   __entry->fence_context = sched_job->s_fence->finished.context;
+			   __entry->fence_seqno = sched_job->s_fence->finished.seqno;
+			   __entry->seq = seq;
+			   __entry->op = op;),
+
+	    TP_printk("fence=(context:%llu, seqno:%llu), %s seq#:%llu %s, op=%u",
+		      __entry->fence_context, __entry->fence_seqno,
+		      __get_str(name), __entry->seq,
+		      __get_str(str),
+		      __entry->op)
+);
+
+DECLARE_EVENT_CLASS(xdna_mbox_msg,
+		    TP_PROTO(char *name, u8 chann_id, u32 opcode, u32 msg_id),
+
+		    TP_ARGS(name, chann_id, opcode, msg_id),
+
+		    TP_STRUCT__entry(__string(name, name)
+				     __field(u32, chann_id)
+				     __field(u32, opcode)
+				     __field(u32, msg_id)),
+
+		    TP_fast_assign(__assign_str(name);
+				   __entry->chann_id = chann_id;
+				   __entry->opcode = opcode;
+				   __entry->msg_id = msg_id;),
+
+		    TP_printk("%s.%d id 0x%x opcode 0x%x", __get_str(name),
+			      __entry->chann_id, __entry->msg_id, __entry->opcode)
+);
+
+DEFINE_EVENT(xdna_mbox_msg, mbox_set_tail,
+	     TP_PROTO(char *name, u8 chann_id, u32 opcode, u32 id),
+	     TP_ARGS(name, chann_id, opcode, id)
+);
+
+DEFINE_EVENT(xdna_mbox_msg, mbox_set_head,
+	     TP_PROTO(char *name, u8 chann_id, u32 opcode, u32 id),
+	     TP_ARGS(name, chann_id, opcode, id)
+);
+
+DECLARE_EVENT_CLASS(xdna_mbox_name_id,
+		    TP_PROTO(char *name, int irq),
+
+		    TP_ARGS(name, irq),
+
+		    TP_STRUCT__entry(__string(name, name)
+				     __field(int, irq)),
+
+		    TP_fast_assign(__assign_str(name);
+				   __entry->irq = irq;),
+
+		    TP_printk("%s.%d", __get_str(name), __entry->irq)
+);
+
+DEFINE_EVENT(xdna_mbox_name_id, mbox_irq_handle,
+	     TP_PROTO(char *name, int irq),
+	     TP_ARGS(name, irq)
+);
+
+DEFINE_EVENT(xdna_mbox_name_id, mbox_rx_worker,
+	     TP_PROTO(char *name, int irq),
+	     TP_ARGS(name, irq)
+);
+
+#endif /* !defined(_TRACE_AMDXDNA_H) || defined(TRACE_HEADER_MULTI_READ) */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>