dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()grafted

When dma_device_put() drops the last reference on chan->device->ref,
dma_device_release() runs and may free the dma_device along with its
channels.

dma_chan_put() then still reads chan->device->owner via
dma_chan_to_owner() for the trailing module_put(). KASAN catches it:

	slab-use-after-free in dma_chan_put+0x3e6/0x4c0
	Read of size 8 by task insmod/6319
	Freed by task 6319:
	  kfree+0x225/0x470
	  dma_chan_put+0x395/0x4c0
	  dmaengine_put+0xf8/0x160

Cache the module owner in dma_chan_put() before the put so the trailing
module_put() does not need chan->device.

Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct")
Suggested-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 79 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-client.h b/sound/soc/sof/sof-client.h
new file mode 100644
index 000000000..3b02506c0
--- /dev/null
+++ b/sound/soc/sof/sof-client.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __SOC_SOF_CLIENT_H
+#define __SOC_SOF_CLIENT_H
+
+#include <linux/auxiliary_bus.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <sound/sof.h>
+
+struct sof_ipc_fw_version;
+struct sof_ipc_cmd_hdr;
+struct snd_sof_dev;
+struct dentry;
+
+struct sof_ipc4_fw_module;
+
+/**
+ * struct sof_client_dev - SOF client device
+ * @auxdev:	auxiliary device
+ * @data:	device specific data
+ */
+struct sof_client_dev {
+	struct auxiliary_device auxdev;
+	void *data;
+};
+
+#define auxiliary_dev_to_sof_client_dev(auxiliary_dev) \
+	container_of(auxiliary_dev, struct sof_client_dev, auxdev)
+
+#define dev_to_sof_client_dev(dev) \
+	container_of(to_auxiliary_dev(dev), struct sof_client_dev, auxdev)
+
+int sof_client_ipc_tx_message(struct sof_client_dev *cdev, void *ipc_msg,
+			      void *reply_data, size_t reply_bytes);
+static inline int sof_client_ipc_tx_message_no_reply(struct sof_client_dev *cdev, void *ipc_msg)
+{
+	return sof_client_ipc_tx_message(cdev, ipc_msg, NULL, 0);
+}
+int sof_client_ipc_set_get_data(struct sof_client_dev *cdev, void *ipc_msg,
+				bool set);
+
+struct sof_ipc4_fw_module *sof_client_ipc4_find_module(struct sof_client_dev *c, const guid_t *u);
+struct snd_sof_widget *sof_client_ipc4_find_swidget_by_id(struct sof_client_dev *cdev,
+							  u32 module_id, int instance_id);
+
+struct dentry *sof_client_get_debugfs_root(struct sof_client_dev *cdev);
+struct device *sof_client_get_dma_dev(struct sof_client_dev *cdev);
+const struct sof_ipc_fw_version *sof_client_get_fw_version(struct sof_client_dev *cdev);
+size_t sof_client_get_ipc_max_payload_size(struct sof_client_dev *cdev);
+enum sof_ipc_type sof_client_get_ipc_type(struct sof_client_dev *cdev);
+
+/* DSP/firmware boot request */
+int sof_client_boot_dsp(struct sof_client_dev *cdev);
+
+/* module refcount management of SOF core */
+int sof_client_core_module_get(struct sof_client_dev *cdev);
+void sof_client_core_module_put(struct sof_client_dev *cdev);
+
+/* IPC notification */
+typedef void (*sof_client_event_callback)(struct sof_client_dev *cdev, void *msg_buf);
+
+int sof_client_register_ipc_rx_handler(struct sof_client_dev *cdev,
+				       u32 ipc_msg_type,
+				       sof_client_event_callback callback);
+void sof_client_unregister_ipc_rx_handler(struct sof_client_dev *cdev,
+					  u32 ipc_msg_type);
+
+/* DSP state notification and query */
+typedef void (*sof_client_fw_state_callback)(struct sof_client_dev *cdev,
+					     enum sof_fw_state state);
+
+int sof_client_register_fw_state_handler(struct sof_client_dev *cdev,
+					 sof_client_fw_state_callback callback);
+void sof_client_unregister_fw_state_handler(struct sof_client_dev *cdev);
+enum sof_fw_state sof_client_get_fw_state(struct sof_client_dev *cdev);
+int sof_client_ipc_rx_message(struct sof_client_dev *cdev, void *ipc_msg, void *msg_buf);
+
+#endif /* __SOC_SOF_CLIENT_H */