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, 239 insertions, 0 deletions

diff --git a/include/trace/events/spi.h b/include/trace/events/spi.h
new file mode 100644
index 000000000..e63d4a24d
--- /dev/null
+++ b/include/trace/events/spi.h
@@ -0,0 +1,239 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM spi
+
+#if !defined(_TRACE_SPI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SPI_H
+
+#include <linux/ktime.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(spi_controller,
+
+	TP_PROTO(struct spi_controller *controller),
+
+	TP_ARGS(controller),
+
+	TP_STRUCT__entry(
+		__field(        int,           bus_num             )
+	),
+
+	TP_fast_assign(
+		__entry->bus_num = controller->bus_num;
+	),
+
+	TP_printk("spi%d", (int)__entry->bus_num)
+
+);
+
+DEFINE_EVENT(spi_controller, spi_controller_idle,
+
+	TP_PROTO(struct spi_controller *controller),
+
+	TP_ARGS(controller)
+
+);
+
+DEFINE_EVENT(spi_controller, spi_controller_busy,
+
+	TP_PROTO(struct spi_controller *controller),
+
+	TP_ARGS(controller)
+
+);
+
+TRACE_EVENT(spi_setup,
+	TP_PROTO(struct spi_device *spi, int status),
+	TP_ARGS(spi, status),
+
+	TP_STRUCT__entry(
+		__field(int, bus_num)
+		__field(int, chip_select)
+		__field(unsigned long, mode)
+		__field(unsigned int, bits_per_word)
+		__field(unsigned int, max_speed_hz)
+		__field(int, status)
+	),
+
+	TP_fast_assign(
+		__entry->bus_num = spi->controller->bus_num;
+		__entry->chip_select =  spi_get_chipselect(spi, 0);
+		__entry->mode = spi->mode;
+		__entry->bits_per_word = spi->bits_per_word;
+		__entry->max_speed_hz = spi->max_speed_hz;
+		__entry->status = status;
+	),
+
+	TP_printk("spi%d.%d setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d",
+		  __entry->bus_num, __entry->chip_select,
+		  (__entry->mode & SPI_MODE_X_MASK),
+		  (__entry->mode & SPI_CS_HIGH) ? "cs_high, " : "",
+		  (__entry->mode & SPI_LSB_FIRST) ? "lsb, " : "",
+		  (__entry->mode & SPI_3WIRE) ? "3wire, " : "",
+		  (__entry->mode & SPI_LOOP) ? "loopback, " : "",
+		  __entry->bits_per_word, __entry->max_speed_hz,
+		  __entry->status)
+);
+
+TRACE_EVENT(spi_set_cs,
+	TP_PROTO(struct spi_device *spi, bool enable),
+	TP_ARGS(spi, enable),
+
+	TP_STRUCT__entry(
+		__field(int, bus_num)
+		__field(int, chip_select)
+		__field(unsigned long, mode)
+		__field(bool, enable)
+	),
+
+	TP_fast_assign(
+		__entry->bus_num = spi->controller->bus_num;
+		__entry->chip_select = spi_get_chipselect(spi, 0);
+		__entry->mode = spi->mode;
+		__entry->enable = enable;
+	),
+
+	TP_printk("spi%d.%d %s%s",
+		  __entry->bus_num, __entry->chip_select,
+		  __entry->enable ? "activate" : "deactivate",
+		  (__entry->mode & SPI_CS_HIGH) ? ", cs_high" : "")
+);
+
+DECLARE_EVENT_CLASS(spi_message,
+
+	TP_PROTO(struct spi_message *msg),
+
+	TP_ARGS(msg),
+
+	TP_STRUCT__entry(
+		__field(        int,            bus_num         )
+		__field(        int,            chip_select     )
+		__field(        struct spi_message *,   msg     )
+	),
+
+	TP_fast_assign(
+		__entry->bus_num = msg->spi->controller->bus_num;
+		__entry->chip_select = spi_get_chipselect(msg->spi, 0);
+		__entry->msg = msg;
+	),
+
+        TP_printk("spi%d.%d %p", (int)__entry->bus_num,
+		  (int)__entry->chip_select,
+		  (struct spi_message *)__entry->msg)
+);
+
+DEFINE_EVENT(spi_message, spi_message_submit,
+
+	TP_PROTO(struct spi_message *msg),
+
+	TP_ARGS(msg)
+
+);
+
+DEFINE_EVENT(spi_message, spi_message_start,
+
+	TP_PROTO(struct spi_message *msg),
+
+	TP_ARGS(msg)
+
+);
+
+TRACE_EVENT(spi_message_done,
+
+	TP_PROTO(struct spi_message *msg),
+
+	TP_ARGS(msg),
+
+	TP_STRUCT__entry(
+		__field(        int,            bus_num         )
+		__field(        int,            chip_select     )
+		__field(        struct spi_message *,   msg     )
+		__field(        unsigned,       frame           )
+		__field(        unsigned,       actual          )
+	),
+
+	TP_fast_assign(
+		__entry->bus_num = msg->spi->controller->bus_num;
+		__entry->chip_select = spi_get_chipselect(msg->spi, 0);
+		__entry->msg = msg;
+		__entry->frame = msg->frame_length;
+		__entry->actual = msg->actual_length;
+	),
+
+        TP_printk("spi%d.%d %p len=%u/%u", (int)__entry->bus_num,
+		  (int)__entry->chip_select,
+		  (struct spi_message *)__entry->msg,
+                  (unsigned)__entry->actual, (unsigned)__entry->frame)
+);
+
+/*
+ * Consider a buffer valid if non-NULL and if it doesn't match the dummy buffer
+ * that only exist to work with controllers that have SPI_CONTROLLER_MUST_TX or
+ * SPI_CONTROLLER_MUST_RX.
+ */
+#define spi_valid_txbuf(msg, xfer) \
+	(xfer->tx_buf && xfer->tx_buf != msg->spi->controller->dummy_tx)
+#define spi_valid_rxbuf(msg, xfer) \
+	(xfer->rx_buf && xfer->rx_buf != msg->spi->controller->dummy_rx)
+
+DECLARE_EVENT_CLASS(spi_transfer,
+
+	TP_PROTO(struct spi_message *msg, struct spi_transfer *xfer),
+
+	TP_ARGS(msg, xfer),
+
+	TP_STRUCT__entry(
+		__field(        int,            bus_num         )
+		__field(        int,            chip_select     )
+		__field(        struct spi_transfer *,   xfer   )
+		__field(        int,            len             )
+		__dynamic_array(u8, rx_buf,
+				spi_valid_rxbuf(msg, xfer) ?
+					(xfer->len < 64 ? xfer->len : 64) : 0)
+		__dynamic_array(u8, tx_buf,
+				spi_valid_txbuf(msg, xfer) ?
+					(xfer->len < 64 ? xfer->len : 64) : 0)
+	),
+
+	TP_fast_assign(
+		__entry->bus_num = msg->spi->controller->bus_num;
+		__entry->chip_select = spi_get_chipselect(msg->spi, 0);
+		__entry->xfer = xfer;
+		__entry->len = xfer->len;
+
+		if (spi_valid_txbuf(msg, xfer))
+			memcpy(__get_dynamic_array(tx_buf),
+			       xfer->tx_buf, __get_dynamic_array_len(tx_buf));
+
+		if (spi_valid_rxbuf(msg, xfer))
+			memcpy(__get_dynamic_array(rx_buf),
+			       xfer->rx_buf, __get_dynamic_array_len(rx_buf));
+	),
+
+	TP_printk("spi%d.%d %p len=%d tx=[%*phD] rx=[%*phD]",
+		  __entry->bus_num, __entry->chip_select,
+		  __entry->xfer, __entry->len,
+		  __get_dynamic_array_len(tx_buf), __get_dynamic_array(tx_buf),
+		  __get_dynamic_array_len(rx_buf), __get_dynamic_array(rx_buf))
+);
+
+DEFINE_EVENT(spi_transfer, spi_transfer_start,
+
+	TP_PROTO(struct spi_message *msg, struct spi_transfer *xfer),
+
+	TP_ARGS(msg, xfer)
+
+);
+
+DEFINE_EVENT(spi_transfer, spi_transfer_stop,
+
+	TP_PROTO(struct spi_message *msg, struct spi_transfer *xfer),
+
+	TP_ARGS(msg, xfer)
+
+);
+
+#endif /* _TRACE_POWER_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>