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, 124 insertions, 0 deletions

diff --git a/include/rdma/opa_smi.h b/include/rdma/opa_smi.h
new file mode 100644
index 000000000..a9f1b5700
--- /dev/null
+++ b/include/rdma/opa_smi.h
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright (c) 2014 Intel Corporation.  All rights reserved.
+ */
+
+#ifndef OPA_SMI_H
+#define OPA_SMI_H
+
+#include <rdma/ib_mad.h>
+#include <rdma/ib_smi.h>
+
+#define OPA_SMP_LID_DATA_SIZE			2016
+#define OPA_SMP_DR_DATA_SIZE			1872
+#define OPA_SMP_MAX_PATH_HOPS			64
+
+#define OPA_MAX_VLS				32
+#define OPA_MAX_SLS				32
+#define OPA_MAX_SCS				32
+
+#define OPA_LID_PERMISSIVE			cpu_to_be32(0xFFFFFFFF)
+
+struct opa_smp {
+	u8	base_version;
+	u8	mgmt_class;
+	u8	class_version;
+	u8	method;
+	__be16	status;
+	u8	hop_ptr;
+	u8	hop_cnt;
+	__be64	tid;
+	__be16	attr_id;
+	__be16	resv;
+	__be32	attr_mod;
+	__be64	mkey;
+	union {
+		struct {
+			uint8_t data[OPA_SMP_LID_DATA_SIZE];
+		} lid;
+		struct {
+			__be32	dr_slid;
+			__be32	dr_dlid;
+			u8	initial_path[OPA_SMP_MAX_PATH_HOPS];
+			u8	return_path[OPA_SMP_MAX_PATH_HOPS];
+			u8	reserved[8];
+			u8	data[OPA_SMP_DR_DATA_SIZE];
+		} dr;
+	} route;
+} __packed;
+
+
+/* Subnet management attributes */
+/* ... */
+#define OPA_ATTRIB_ID_NODE_DESCRIPTION		cpu_to_be16(0x0010)
+#define OPA_ATTRIB_ID_NODE_INFO			cpu_to_be16(0x0011)
+#define OPA_ATTRIB_ID_PORT_INFO			cpu_to_be16(0x0015)
+#define OPA_ATTRIB_ID_PARTITION_TABLE		cpu_to_be16(0x0016)
+#define OPA_ATTRIB_ID_SL_TO_SC_MAP		cpu_to_be16(0x0017)
+#define OPA_ATTRIB_ID_VL_ARBITRATION		cpu_to_be16(0x0018)
+#define OPA_ATTRIB_ID_SM_INFO			cpu_to_be16(0x0020)
+#define OPA_ATTRIB_ID_CABLE_INFO		cpu_to_be16(0x0032)
+#define OPA_ATTRIB_ID_AGGREGATE			cpu_to_be16(0x0080)
+#define OPA_ATTRIB_ID_SC_TO_SL_MAP		cpu_to_be16(0x0082)
+#define OPA_ATTRIB_ID_SC_TO_VLR_MAP		cpu_to_be16(0x0083)
+#define OPA_ATTRIB_ID_SC_TO_VLT_MAP		cpu_to_be16(0x0084)
+#define OPA_ATTRIB_ID_SC_TO_VLNT_MAP		cpu_to_be16(0x0085)
+/* ... */
+#define OPA_ATTRIB_ID_PORT_STATE_INFO		cpu_to_be16(0x0087)
+/* ... */
+#define OPA_ATTRIB_ID_BUFFER_CONTROL_TABLE	cpu_to_be16(0x008A)
+/* ... */
+
+struct opa_node_description {
+	u8 data[64];
+} __packed;
+
+struct opa_node_info {
+	u8      base_version;
+	u8      class_version;
+	u8      node_type;
+	u8      num_ports;
+	__be32  reserved;
+	__be64  system_image_guid;
+	__be64  node_guid;
+	__be64  port_guid;
+	__be16  partition_cap;
+	__be16  device_id;
+	__be32  revision;
+	u8      local_port_num;
+	u8      vendor_id[3];   /* network byte order */
+} __packed;
+
+#define OPA_PARTITION_TABLE_BLK_SIZE 32
+
+static inline u8
+opa_get_smp_direction(struct opa_smp *smp)
+{
+	return ib_get_smp_direction((struct ib_smp *)smp);
+}
+
+static inline u8 *opa_get_smp_data(struct opa_smp *smp)
+{
+	if (smp->mgmt_class == IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
+		return smp->route.dr.data;
+
+	return smp->route.lid.data;
+}
+
+static inline size_t opa_get_smp_data_size(struct opa_smp *smp)
+{
+	if (smp->mgmt_class == IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
+		return sizeof(smp->route.dr.data);
+
+	return sizeof(smp->route.lid.data);
+}
+
+static inline size_t opa_get_smp_header_size(struct opa_smp *smp)
+{
+	if (smp->mgmt_class == IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE)
+		return sizeof(*smp) - sizeof(smp->route.dr.data);
+
+	return sizeof(*smp) - sizeof(smp->route.lid.data);
+}
+
+#endif /* OPA_SMI_H */