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, 106 insertions, 0 deletions

diff --git a/include/trace/events/spi-mem.h b/include/trace/events/spi-mem.h
new file mode 100644
index 000000000..d13f0bcff
--- /dev/null
+++ b/include/trace/events/spi-mem.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM spi-mem
+
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR spi_mem
+
+#if !defined(_TRACE_SPI_MEM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SPI_MEM_H
+
+#include <linux/tracepoint.h>
+#include <linux/spi/spi-mem.h>
+
+#define decode_dtr(dtr) \
+	__print_symbolic(dtr, \
+		{ 0, "S" }, \
+		{ 1, "D" })
+
+TRACE_EVENT(spi_mem_start_op,
+	TP_PROTO(struct spi_mem *mem, const struct spi_mem_op *op),
+	TP_ARGS(mem, op),
+
+	TP_STRUCT__entry(
+		__string(name, mem->name)
+		__dynamic_array(u8, op, 1 + op->addr.nbytes + op->dummy.nbytes)
+		__dynamic_array(u8, data, op->data.dir == SPI_MEM_DATA_OUT ?
+					  min(op->data.nbytes, 64) : 0)
+		__field(u32, data_len)
+		__field(u32, max_freq)
+		__field(u8, cmd_buswidth)
+		__field(bool, cmd_dtr)
+		__field(u8, addr_buswidth)
+		__field(bool, addr_dtr)
+		__field(u8, dummy_nbytes)
+		__field(u8, data_buswidth)
+		__field(bool, data_dtr)
+	),
+
+	TP_fast_assign(
+		int i;
+
+		__assign_str(name);
+		__entry->max_freq = op->max_freq ?: mem->spi->max_speed_hz;
+
+		__entry->cmd_buswidth = op->cmd.buswidth;
+		__entry->cmd_dtr = op->cmd.dtr;
+		*((u8 *)__get_dynamic_array(op)) = op->cmd.opcode;
+
+		__entry->addr_buswidth = op->addr.buswidth;
+		__entry->addr_dtr = op->addr.dtr;
+		for (i = 0; i < op->addr.nbytes; i++)
+			((u8 *)__get_dynamic_array(op))[i + 1] =
+				op->addr.val >> (8 * (op->addr.nbytes - i - 1));
+
+		memset(((u8 *)__get_dynamic_array(op)) + op->addr.nbytes + 1,
+		       0xff, op->dummy.nbytes);
+
+		__entry->data_len = op->data.nbytes;
+		__entry->data_buswidth = op->data.buswidth;
+		__entry->data_dtr = op->data.dtr;
+		if (op->data.dir == SPI_MEM_DATA_OUT)
+			memcpy(__get_dynamic_array(data), op->data.buf.out,
+			       __get_dynamic_array_len(data));
+	),
+
+	TP_printk("%s %u%s-%u%s-%u%s @%u Hz op=[%*phD] len=%u tx=[%*phD]",
+		__get_str(name),
+		__entry->cmd_buswidth, decode_dtr(__entry->cmd_dtr),
+		__entry->addr_buswidth, decode_dtr(__entry->addr_dtr),
+		__entry->data_buswidth, decode_dtr(__entry->data_dtr),
+		__entry->max_freq,
+		__get_dynamic_array_len(op), __get_dynamic_array(op),
+		__entry->data_len,
+		__get_dynamic_array_len(data), __get_dynamic_array(data))
+);
+
+TRACE_EVENT(spi_mem_stop_op,
+	TP_PROTO(struct spi_mem *mem, const struct spi_mem_op *op),
+	TP_ARGS(mem, op),
+
+	TP_STRUCT__entry(
+		__string(name, mem->name)
+		__dynamic_array(u8, data, op->data.dir == SPI_MEM_DATA_IN ?
+					  min(op->data.nbytes, 64) : 0)
+		__field(u32, data_len)
+	),
+
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->data_len = op->data.nbytes;
+		if (op->data.dir == SPI_MEM_DATA_IN)
+			memcpy(__get_dynamic_array(data), op->data.buf.in,
+			       __get_dynamic_array_len(data));
+	),
+
+	TP_printk("%s len=%u rx=[%*phD]",
+		__get_str(name),
+		__entry->data_len,
+		__get_dynamic_array_len(data), __get_dynamic_array(data))
+);
+
+
+#endif /* _TRACE_SPI_MEM_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>