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, 104 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-of-dev.c b/sound/soc/sof/sof-of-dev.c
new file mode 100644
index 000000000..3ccfcfb14
--- /dev/null
+++ b/sound/soc/sof/sof-of-dev.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// Copyright 2019 NXP
+//
+// Author: Daniel Baluta <daniel.baluta@nxp.com>
+//
+
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/pm_runtime.h>
+#include <sound/sof.h>
+
+#include "sof-of-dev.h"
+#include "ops.h"
+
+static char *fw_path;
+module_param(fw_path, charp, 0444);
+MODULE_PARM_DESC(fw_path, "deprecated - moved to snd-sof module.");
+
+static char *fw_filename;
+module_param(fw_filename, charp, 0444);
+MODULE_PARM_DESC(fw_filename, "deprecated - moved to snd-sof module.");
+
+static char *tplg_path;
+module_param(tplg_path, charp, 0444);
+MODULE_PARM_DESC(tplg_path, "deprecated - moved to snd-sof module.");
+
+static char *tplg_filename;
+module_param(tplg_filename, charp, 0444);
+MODULE_PARM_DESC(tplg_filename, "deprecated - moved to snd-sof module.");
+
+EXPORT_DEV_PM_OPS(sof_of_pm) = {
+	.prepare = snd_sof_prepare,
+	.complete = snd_sof_complete,
+	SYSTEM_SLEEP_PM_OPS(snd_sof_suspend, snd_sof_resume)
+	RUNTIME_PM_OPS(snd_sof_runtime_suspend, snd_sof_runtime_resume, NULL)
+};
+
+static void sof_of_probe_complete(struct device *dev)
+{
+	/* allow runtime_pm */
+	pm_runtime_set_autosuspend_delay(dev, SND_SOF_SUSPEND_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+}
+
+int sof_of_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct sof_dev_desc *desc;
+	struct snd_sof_pdata *sof_pdata;
+
+	dev_info(&pdev->dev, "DT DSP detected");
+
+	sof_pdata = devm_kzalloc(dev, sizeof(*sof_pdata), GFP_KERNEL);
+	if (!sof_pdata)
+		return -ENOMEM;
+
+	desc = device_get_match_data(dev);
+	if (!desc)
+		return -ENODEV;
+
+	if (!desc->ops) {
+		dev_err(dev, "error: no matching DT descriptor ops\n");
+		return -ENODEV;
+	}
+
+	sof_pdata->desc = desc;
+	sof_pdata->dev = &pdev->dev;
+
+	sof_pdata->ipc_file_profile_base.ipc_type = desc->ipc_default;
+	sof_pdata->ipc_file_profile_base.fw_path = fw_path;
+	sof_pdata->ipc_file_profile_base.tplg_path = tplg_path;
+	sof_pdata->ipc_file_profile_base.fw_name = fw_filename;
+	sof_pdata->ipc_file_profile_base.tplg_name = tplg_filename;
+
+	/* set callback to be called on successful device probe to enable runtime_pm */
+	sof_pdata->sof_probe_complete = sof_of_probe_complete;
+
+	/* call sof helper for DSP hardware probe */
+	return snd_sof_device_probe(dev, sof_pdata);
+}
+EXPORT_SYMBOL(sof_of_probe);
+
+void sof_of_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+
+	/* call sof helper for DSP hardware remove */
+	snd_sof_device_remove(&pdev->dev);
+}
+EXPORT_SYMBOL(sof_of_remove);
+
+void sof_of_shutdown(struct platform_device *pdev)
+{
+	snd_sof_device_shutdown(&pdev->dev);
+}
+EXPORT_SYMBOL(sof_of_shutdown);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("SOF support for OF/DT platforms");