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, 78 insertions, 0 deletions

diff --git a/include/trace/events/mctp.h b/include/trace/events/mctp.h
new file mode 100644
index 000000000..165cf25f7
--- /dev/null
+++ b/include/trace/events/mctp.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mctp
+
+#if !defined(_TRACE_MCTP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_MCTP_H
+
+#include <linux/tracepoint.h>
+
+#ifndef __TRACE_MCTP_ENUMS
+#define __TRACE_MCTP_ENUMS
+enum {
+	MCTP_TRACE_KEY_TIMEOUT,
+	MCTP_TRACE_KEY_REPLIED,
+	MCTP_TRACE_KEY_INVALIDATED,
+	MCTP_TRACE_KEY_CLOSED,
+	MCTP_TRACE_KEY_DROPPED,
+};
+#endif /* __TRACE_MCTP_ENUMS */
+
+TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_TIMEOUT);
+TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_REPLIED);
+TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_INVALIDATED);
+TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_CLOSED);
+TRACE_DEFINE_ENUM(MCTP_TRACE_KEY_DROPPED);
+
+TRACE_EVENT(mctp_key_acquire,
+	TP_PROTO(const struct mctp_sk_key *key),
+	TP_ARGS(key),
+	TP_STRUCT__entry(
+		__field(__u8,	paddr)
+		__field(__u8,	laddr)
+		__field(__u8,	tag)
+	),
+	TP_fast_assign(
+		__entry->paddr = key->peer_addr;
+		__entry->laddr = key->local_addr;
+		__entry->tag = key->tag;
+	),
+	TP_printk("local %d, peer %d, tag %1x",
+		__entry->laddr,
+		__entry->paddr,
+		__entry->tag
+	)
+);
+
+TRACE_EVENT(mctp_key_release,
+	TP_PROTO(const struct mctp_sk_key *key, int reason),
+	TP_ARGS(key, reason),
+	TP_STRUCT__entry(
+		__field(__u8,	paddr)
+		__field(__u8,	laddr)
+		__field(__u8,	tag)
+		__field(int,	reason)
+	),
+	TP_fast_assign(
+		__entry->paddr = key->peer_addr;
+		__entry->laddr = key->local_addr;
+		__entry->tag = key->tag;
+		__entry->reason = reason;
+	),
+	TP_printk("local %d, peer %d, tag %1x %s",
+		__entry->laddr,
+		__entry->paddr,
+		__entry->tag,
+		__print_symbolic(__entry->reason,
+				 { MCTP_TRACE_KEY_TIMEOUT, "timeout" },
+				 { MCTP_TRACE_KEY_REPLIED, "replied" },
+				 { MCTP_TRACE_KEY_INVALIDATED, "invalidated" },
+				 { MCTP_TRACE_KEY_CLOSED, "closed" },
+				 { MCTP_TRACE_KEY_DROPPED, "dropped" })
+	)
+);
+
+#endif
+
+#include <trace/define_trace.h>