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, 99 insertions, 0 deletions

diff --git a/net/bluetooth/eir.h b/net/bluetooth/eir.h
new file mode 100644
index 000000000..9372db83f
--- /dev/null
+++ b/net/bluetooth/eir.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * BlueZ - Bluetooth protocol stack for Linux
+ *
+ * Copyright (C) 2021 Intel Corporation
+ */
+
+#include <linux/unaligned.h>
+
+void eir_create(struct hci_dev *hdev, u8 *data);
+
+u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr, u8 size);
+u8 eir_create_scan_rsp(struct hci_dev *hdev, u8 instance, u8 *ptr);
+u8 eir_create_per_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr);
+
+u8 eir_append_local_name(struct hci_dev *hdev, u8 *eir, u8 ad_len);
+u8 eir_append_appearance(struct hci_dev *hdev, u8 *ptr, u8 ad_len);
+u8 eir_append_service_data(u8 *eir, u16 eir_len, u16 uuid, u8 *data,
+			   u8 data_len);
+
+static inline u16 eir_precalc_len(u8 data_len)
+{
+	return sizeof(u8) * 2 + data_len;
+}
+
+static inline u16 eir_append_data(u8 *eir, u16 eir_len, u8 type,
+				  u8 *data, u8 data_len)
+{
+	eir[eir_len++] = sizeof(type) + data_len;
+	eir[eir_len++] = type;
+	memcpy(&eir[eir_len], data, data_len);
+	eir_len += data_len;
+
+	return eir_len;
+}
+
+static inline u16 eir_append_le16(u8 *eir, u16 eir_len, u8 type, u16 data)
+{
+	eir[eir_len++] = sizeof(type) + sizeof(data);
+	eir[eir_len++] = type;
+	put_unaligned_le16(data, &eir[eir_len]);
+	eir_len += sizeof(data);
+
+	return eir_len;
+}
+
+static inline u16 eir_skb_put_data(struct sk_buff *skb, u8 type, u8 *data, u8 data_len)
+{
+	u8 *eir;
+	u16 eir_len;
+
+	eir_len	= eir_precalc_len(data_len);
+	eir = skb_put(skb, eir_len);
+	WARN_ON(sizeof(type) + data_len > U8_MAX);
+	eir[0] = sizeof(type) + data_len;
+	eir[1] = type;
+	memcpy(&eir[2], data, data_len);
+
+	return eir_len;
+}
+
+static inline void *eir_get_data(u8 *eir, size_t eir_len, u8 type,
+				 size_t *data_len)
+{
+	size_t parsed = 0;
+
+	if (eir_len < 2)
+		return NULL;
+
+	while (parsed < eir_len - 1) {
+		u8 field_len = eir[0];
+
+		if (field_len == 0)
+			break;
+
+		parsed += field_len + 1;
+
+		if (parsed > eir_len)
+			break;
+
+		if (eir[1] != type) {
+			eir += field_len + 1;
+			continue;
+		}
+
+		/* Zero length data */
+		if (field_len == 1)
+			return NULL;
+
+		if (data_len)
+			*data_len = field_len - 1;
+
+		return &eir[2];
+	}
+
+	return NULL;
+}
+
+void *eir_get_service_data(u8 *eir, size_t eir_len, u16 uuid, size_t *len);