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, 117 insertions, 0 deletions

diff --git a/drivers/bluetooth/btbcm.h b/drivers/bluetooth/btbcm.h
new file mode 100644
index 000000000..b4cb24231
--- /dev/null
+++ b/drivers/bluetooth/btbcm.h
@@ -0,0 +1,117 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *
+ *  Bluetooth support for Broadcom devices
+ *
+ *  Copyright (C) 2015  Intel Corporation
+ */
+
+#define BCM_UART_CLOCK_48MHZ	0x01
+#define BCM_UART_CLOCK_24MHZ	0x02
+
+struct bcm_update_uart_baud_rate {
+	__le16 zero;
+	__le32 baud_rate;
+} __packed;
+
+struct bcm_write_uart_clock_setting {
+	__u8 type;
+} __packed;
+
+struct bcm_set_sleep_mode {
+	__u8 sleep_mode;
+	__u8 idle_host;
+	__u8 idle_dev;
+	__u8 bt_wake_active;
+	__u8 host_wake_active;
+	__u8 allow_host_sleep;
+	__u8 combine_modes;
+	__u8 tristate_control;
+	__u8 usb_auto_sleep;
+	__u8 usb_resume_timeout;
+	__u8 break_to_host;
+	__u8 pulsed_host_wake;
+} __packed;
+
+struct bcm_set_pcm_int_params {
+	__u8 routing;
+	__u8 rate;
+	__u8 frame_sync;
+	__u8 sync_mode;
+	__u8 clock_mode;
+} __packed;
+
+struct bcm_set_pcm_format_params {
+	__u8 lsb_first;
+	__u8 fill_value;
+	__u8 fill_method;
+	__u8 fill_num;
+	__u8 right_justify;
+} __packed;
+
+#if IS_ENABLED(CONFIG_BT_BCM)
+
+int btbcm_check_bdaddr(struct hci_dev *hdev);
+int btbcm_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr);
+int btbcm_patchram(struct hci_dev *hdev, const struct firmware *fw);
+int btbcm_read_pcm_int_params(struct hci_dev *hdev,
+			      struct bcm_set_pcm_int_params *params);
+int btbcm_write_pcm_int_params(struct hci_dev *hdev,
+			       const struct bcm_set_pcm_int_params *params);
+
+int btbcm_setup_patchram(struct hci_dev *hdev);
+int btbcm_setup_apple(struct hci_dev *hdev);
+
+int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode);
+int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode);
+
+#else
+
+static inline int btbcm_check_bdaddr(struct hci_dev *hdev)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_read_pcm_int_params(struct hci_dev *hdev,
+			      struct bcm_set_pcm_int_params *params)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_write_pcm_int_params(struct hci_dev *hdev,
+			       const struct bcm_set_pcm_int_params *params)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_patchram(struct hci_dev *hdev, const struct firmware *fw)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int btbcm_setup_patchram(struct hci_dev *hdev)
+{
+	return 0;
+}
+
+static inline int btbcm_setup_apple(struct hci_dev *hdev)
+{
+	return 0;
+}
+
+static inline int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
+{
+	return 0;
+}
+
+static inline int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode)
+{
+	return 0;
+}
+
+#endif