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, 88 insertions, 0 deletions

diff --git a/drivers/interconnect/trace.h b/drivers/interconnect/trace.h
new file mode 100644
index 000000000..206373546
--- /dev/null
+++ b/drivers/interconnect/trace.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Interconnect framework tracepoints
+ * Copyright (c) 2019, Linaro Ltd.
+ * Author: Georgi Djakov <georgi.djakov@linaro.org>
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM interconnect
+
+#if !defined(_TRACE_INTERCONNECT_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_INTERCONNECT_H
+
+#include <linux/interconnect.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(icc_set_bw,
+
+	TP_PROTO(struct icc_path *p, struct icc_node *n, int i,
+		 u32 avg_bw, u32 peak_bw),
+
+	TP_ARGS(p, n, i, avg_bw, peak_bw),
+
+	TP_STRUCT__entry(
+		__string(path_name, p->name)
+		__string(dev, dev_name(p->reqs[i].dev))
+		__string(node_name, n->name)
+		__field(u32, avg_bw)
+		__field(u32, peak_bw)
+		__field(u32, node_avg_bw)
+		__field(u32, node_peak_bw)
+	),
+
+	TP_fast_assign(
+		__assign_str(path_name);
+		__assign_str(dev);
+		__assign_str(node_name);
+		__entry->avg_bw = avg_bw;
+		__entry->peak_bw = peak_bw;
+		__entry->node_avg_bw = n->avg_bw;
+		__entry->node_peak_bw = n->peak_bw;
+	),
+
+	TP_printk("path=%s dev=%s node=%s avg_bw=%u peak_bw=%u agg_avg=%u agg_peak=%u",
+		  __get_str(path_name),
+		  __get_str(dev),
+		  __get_str(node_name),
+		  __entry->avg_bw,
+		  __entry->peak_bw,
+		  __entry->node_avg_bw,
+		  __entry->node_peak_bw)
+);
+
+TRACE_EVENT(icc_set_bw_end,
+
+	TP_PROTO(struct icc_path *p, int ret),
+
+	TP_ARGS(p, ret),
+
+	TP_STRUCT__entry(
+		__string(path_name, p->name)
+		__string(dev, dev_name(p->reqs[0].dev))
+		__field(int, ret)
+	),
+
+	TP_fast_assign(
+		__assign_str(path_name);
+		__assign_str(dev);
+		__entry->ret = ret;
+	),
+
+	TP_printk("path=%s dev=%s ret=%d",
+		  __get_str(path_name),
+		  __get_str(dev),
+		  __entry->ret)
+);
+
+#endif /* _TRACE_INTERCONNECT_H */
+
+/* This part must be outside protection */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>