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, 68 insertions, 0 deletions

diff --git a/include/net/sctp/ulpqueue.h b/include/net/sctp/ulpqueue.h
new file mode 100644
index 000000000..60f664129
--- /dev/null
+++ b/include/net/sctp/ulpqueue.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2001, 2004
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001 Intel Corp.
+ * Copyright (c) 2001 Nokia, Inc.
+ * Copyright (c) 2001 La Monte H.P. Yarroll
+ *
+ * These are the definitions needed for the sctp_ulpq type.  The
+ * sctp_ulpq is the interface between the Upper Layer Protocol, or ULP,
+ * and the core SCTP state machine.  This is the component which handles
+ * reassembly and ordering.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email addresses:
+ *    lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ *   Jon Grimm             <jgrimm@us.ibm.com>
+ *   La Monte H.P. Yarroll <piggy@acm.org>
+ *   Sridhar Samudrala     <sri@us.ibm.com>
+ */
+
+#ifndef __sctp_ulpqueue_h__
+#define __sctp_ulpqueue_h__
+
+/* A structure to carry information to the ULP (e.g. Sockets API) */
+struct sctp_ulpq {
+	char pd_mode;
+	struct sctp_association *asoc;
+	struct sk_buff_head reasm;
+	struct sk_buff_head reasm_uo;
+	struct sk_buff_head lobby;
+};
+
+/* Prototypes. */
+void sctp_ulpq_init(struct sctp_ulpq *ulpq, struct sctp_association *asoc);
+void sctp_ulpq_flush(struct sctp_ulpq *ulpq);
+void sctp_ulpq_free(struct sctp_ulpq *);
+
+/* Add a new DATA chunk for processing. */
+int sctp_ulpq_tail_data(struct sctp_ulpq *, struct sctp_chunk *, gfp_t);
+
+/* Add a new event for propagation to the ULP. */
+int sctp_ulpq_tail_event(struct sctp_ulpq *, struct sk_buff_head *skb_list);
+
+/* Renege previously received chunks.  */
+void sctp_ulpq_renege(struct sctp_ulpq *, struct sctp_chunk *, gfp_t);
+
+/* Perform partial delivery. */
+void sctp_ulpq_partial_delivery(struct sctp_ulpq *, gfp_t);
+
+/* Abort the partial delivery. */
+void sctp_ulpq_abort_pd(struct sctp_ulpq *, gfp_t);
+
+/* Clear the partial data delivery condition on this socket. */
+int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc);
+
+/* Skip over an SSN. */
+void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn);
+
+void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *, __u32);
+
+__u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
+			    struct sk_buff_head *list, __u16 needed);
+
+#endif /* __sctp_ulpqueue_h__ */