From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() 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 Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- drivers/scsi/arm/msgqueue.h | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 drivers/scsi/arm/msgqueue.h (limited to 'drivers/scsi/arm/msgqueue.h') diff --git a/drivers/scsi/arm/msgqueue.h b/drivers/scsi/arm/msgqueue.h new file mode 100644 index 000000000..4bcc400f5 --- /dev/null +++ b/drivers/scsi/arm/msgqueue.h @@ -0,0 +1,79 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/drivers/acorn/scsi/msgqueue.h + * + * Copyright (C) 1997 Russell King + * + * message queue handling + */ +#ifndef MSGQUEUE_H +#define MSGQUEUE_H + +struct message { + char msg[8]; + int length; + int fifo; +}; + +struct msgqueue_entry { + struct message msg; + struct msgqueue_entry *next; +}; + +#define NR_MESSAGES 4 + +typedef struct { + struct msgqueue_entry *qe; + struct msgqueue_entry *free; + struct msgqueue_entry entries[NR_MESSAGES]; +} MsgQueue_t; + +/* + * Function: void msgqueue_initialise(MsgQueue_t *msgq) + * Purpose : initialise a message queue + * Params : msgq - queue to initialise + */ +extern void msgqueue_initialise(MsgQueue_t *msgq); + +/* + * Function: void msgqueue_free(MsgQueue_t *msgq) + * Purpose : free a queue + * Params : msgq - queue to free + */ +extern void msgqueue_free(MsgQueue_t *msgq); + +/* + * Function: int msgqueue_msglength(MsgQueue_t *msgq) + * Purpose : calculate the total length of all messages on the message queue + * Params : msgq - queue to examine + * Returns : number of bytes of messages in queue + */ +extern int msgqueue_msglength(MsgQueue_t *msgq); + +/* + * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) + * Purpose : return a message & its length + * Params : msgq - queue to obtain message from + * : msgno - message number + * Returns : pointer to message string, or NULL + */ +extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno); + +/* + * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) + * Purpose : add a message onto a message queue + * Params : msgq - queue to add message on + * length - length of message + * ... - message bytes + * Returns : != 0 if successful + */ +extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...); + +/* + * Function: void msgqueue_flush(MsgQueue_t *msgq) + * Purpose : flush all messages from message queue + * Params : msgq - queue to flush + */ +extern void msgqueue_flush(MsgQueue_t *msgq); + +#endif -- cgit v1.3.1