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, 53 insertions, 0 deletions

diff --git a/sound/soc/sof/trace.c b/sound/soc/sof/trace.c
new file mode 100644
index 000000000..fe6c67c01
--- /dev/null
+++ b/sound/soc/sof/trace.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright(c) 2022 Intel Corporation
+
+#include "sof-priv.h"
+
+int sof_fw_trace_init(struct snd_sof_dev *sdev)
+{
+	const struct sof_ipc_fw_tracing_ops *fw_tracing = sof_ipc_get_ops(sdev, fw_tracing);
+
+	if (!fw_tracing) {
+		dev_info(sdev->dev, "Firmware tracing is not available\n");
+		sdev->fw_trace_is_supported = false;
+
+		return 0;
+	}
+
+	return fw_tracing->init(sdev);
+}
+
+void sof_fw_trace_free(struct snd_sof_dev *sdev)
+{
+	if (!sdev->fw_trace_is_supported)
+		return;
+
+	if (sdev->ipc->ops->fw_tracing->free)
+		sdev->ipc->ops->fw_tracing->free(sdev);
+}
+
+void sof_fw_trace_fw_crashed(struct snd_sof_dev *sdev)
+{
+	if (!sdev->fw_trace_is_supported)
+		return;
+
+	if (sdev->ipc->ops->fw_tracing->fw_crashed)
+		sdev->ipc->ops->fw_tracing->fw_crashed(sdev);
+}
+
+void sof_fw_trace_suspend(struct snd_sof_dev *sdev, pm_message_t pm_state)
+{
+	if (!sdev->fw_trace_is_supported)
+		return;
+
+	sdev->ipc->ops->fw_tracing->suspend(sdev, pm_state);
+}
+
+int sof_fw_trace_resume(struct snd_sof_dev *sdev)
+{
+	if (!sdev->fw_trace_is_supported)
+		return 0;
+
+	return sdev->ipc->ops->fw_tracing->resume(sdev);
+}