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, 52 insertions, 0 deletions

diff --git a/include/trace/events/udp.h b/include/trace/events/udp.h
new file mode 100644
index 000000000..6142be406
--- /dev/null
+++ b/include/trace/events/udp.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM udp
+
+#if !defined(_TRACE_UDP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_UDP_H
+
+#include <linux/udp.h>
+#include <linux/tracepoint.h>
+#include <trace/events/net_probe_common.h>
+
+TRACE_EVENT(udp_fail_queue_rcv_skb,
+
+	TP_PROTO(int rc, struct sock *sk, struct sk_buff *skb),
+
+	TP_ARGS(rc, sk, skb),
+
+	TP_STRUCT__entry(
+		__field(int, rc)
+
+		__field(__u16, sport)
+		__field(__u16, dport)
+		__field(__u16, family)
+		__array(__u8, saddr, sizeof(struct sockaddr_in6))
+		__array(__u8, daddr, sizeof(struct sockaddr_in6))
+	),
+
+	TP_fast_assign(
+		const struct udphdr *uh = (const struct udphdr *)udp_hdr(skb);
+
+		__entry->rc = rc;
+
+		/* for filtering use */
+		__entry->sport = ntohs(uh->source);
+		__entry->dport = ntohs(uh->dest);
+		__entry->family = sk->sk_family;
+
+		memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
+		memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
+
+		TP_STORE_ADDR_PORTS_SKB(skb, uh, __entry->saddr, __entry->daddr);
+	),
+
+	TP_printk("rc=%d family=%s src=%pISpc dest=%pISpc", __entry->rc,
+		  show_family_name(__entry->family),
+		  __entry->saddr, __entry->daddr)
+);
+
+#endif /* _TRACE_UDP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>