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, 95 insertions, 0 deletions

diff --git a/include/trace/events/mce.h b/include/trace/events/mce.h
new file mode 100644
index 000000000..c1c50df9e
--- /dev/null
+++ b/include/trace/events/mce.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mce
+
+#if !defined(_TRACE_MCE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_MCE_H
+
+#include <linux/ktime.h>
+#include <linux/tracepoint.h>
+#include <asm/mce.h>
+
+/*
+ * MCE Event Record.
+ *
+ * Only very relevant and transient information which cannot be
+ * gathered from a system by any other means or which can only be
+ * acquired arduously should be added to this record.
+ */
+
+TRACE_EVENT(mce_record,
+
+	TP_PROTO(struct mce_hw_err *err),
+
+	TP_ARGS(err),
+
+	TP_STRUCT__entry(
+		__field(	u64,		mcgcap		)
+		__field(	u64,		mcgstatus	)
+		__field(	u64,		status		)
+		__field(	u64,		addr		)
+		__field(	u64,		misc		)
+		__field(	u64,		synd		)
+		__field(	u64,		ipid		)
+		__field(	u64,		ip		)
+		__field(	u64,		tsc		)
+		__field(	u64,		ppin		)
+		__field(	u64,		walltime	)
+		__field(	u32,		cpu		)
+		__field(	u32,		cpuid		)
+		__field(	u32,		apicid		)
+		__field(	u32,		socketid	)
+		__field(	u8,		cs		)
+		__field(	u8,		bank		)
+		__field(	u8,		cpuvendor	)
+		__field(	u32,		microcode	)
+		__dynamic_array(u8, v_data, sizeof(err->vendor))
+	),
+
+	TP_fast_assign(
+		__entry->mcgcap		= err->m.mcgcap;
+		__entry->mcgstatus	= err->m.mcgstatus;
+		__entry->status		= err->m.status;
+		__entry->addr		= err->m.addr;
+		__entry->misc		= err->m.misc;
+		__entry->synd		= err->m.synd;
+		__entry->ipid		= err->m.ipid;
+		__entry->ip		= err->m.ip;
+		__entry->tsc		= err->m.tsc;
+		__entry->ppin		= err->m.ppin;
+		__entry->walltime	= err->m.time;
+		__entry->cpu		= err->m.extcpu;
+		__entry->cpuid		= err->m.cpuid;
+		__entry->apicid		= err->m.apicid;
+		__entry->socketid	= err->m.socketid;
+		__entry->cs		= err->m.cs;
+		__entry->bank		= err->m.bank;
+		__entry->cpuvendor	= err->m.cpuvendor;
+		__entry->microcode	= err->m.microcode;
+		memcpy(__get_dynamic_array(v_data), &err->vendor, sizeof(err->vendor));
+	),
+
+	TP_printk("CPU: %d, MCGc/s: %llx/%llx, MC%d: %016llx, IPID: %016llx, ADDR: %016llx, MISC: %016llx, SYND: %016llx, RIP: %02x:<%016llx>, TSC: %llx, PPIN: %llx, vendor: %u, CPUID: %x, time: %llu, socket: %u, APIC: %x, microcode: %x, vendor data: %s",
+		__entry->cpu,
+		__entry->mcgcap, __entry->mcgstatus,
+		__entry->bank, __entry->status,
+		__entry->ipid,
+		__entry->addr,
+		__entry->misc,
+		__entry->synd,
+		__entry->cs, __entry->ip,
+		__entry->tsc,
+		__entry->ppin,
+		__entry->cpuvendor,
+		__entry->cpuid,
+		__entry->walltime,
+		__entry->socketid,
+		__entry->apicid,
+		__entry->microcode,
+		__print_dynamic_array(v_data, sizeof(u8)))
+);
+
+#endif /* _TRACE_MCE_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>