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, 67 insertions, 0 deletions

diff --git a/include/trace/events/icmp.h b/include/trace/events/icmp.h
new file mode 100644
index 000000000..09ae11509
--- /dev/null
+++ b/include/trace/events/icmp.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM icmp
+
+#if !defined(_TRACE_ICMP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ICMP_H
+
+#include <linux/icmp.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(icmp_send,
+
+		TP_PROTO(const struct sk_buff *skb, int type, int code),
+
+		TP_ARGS(skb, type, code),
+
+		TP_STRUCT__entry(
+			__field(const void *, skbaddr)
+			__field(int, type)
+			__field(int, code)
+			__array(__u8, saddr, 4)
+			__array(__u8, daddr, 4)
+			__field(__u16, sport)
+			__field(__u16, dport)
+			__field(unsigned short, ulen)
+		),
+
+		TP_fast_assign(
+			struct iphdr *iph = ip_hdr(skb);
+			struct udphdr *uh = udp_hdr(skb);
+			int proto_4 = iph->protocol;
+			__be32 *p32;
+
+			__entry->skbaddr = skb;
+			__entry->type = type;
+			__entry->code = code;
+
+			if (proto_4 != IPPROTO_UDP || (u8 *)uh < skb->head ||
+				(u8 *)uh + sizeof(struct udphdr)
+				> skb_tail_pointer(skb)) {
+				__entry->sport = 0;
+				__entry->dport = 0;
+				__entry->ulen = 0;
+			} else {
+				__entry->sport = ntohs(uh->source);
+				__entry->dport = ntohs(uh->dest);
+				__entry->ulen = udp_get_len_short(uh);
+			}
+
+			p32 = (__be32 *) __entry->saddr;
+			*p32 = iph->saddr;
+
+			p32 = (__be32 *) __entry->daddr;
+			*p32 = iph->daddr;
+		),
+
+		TP_printk("icmp_send: type=%d, code=%d. From %pI4:%u to %pI4:%u ulen=%d skbaddr=%p",
+			__entry->type, __entry->code,
+			__entry->saddr, __entry->sport, __entry->daddr,
+			__entry->dport, __entry->ulen, __entry->skbaddr)
+);
+
+#endif /* _TRACE_ICMP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
+