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/rpmsg/rpmsg_char.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 drivers/rpmsg/rpmsg_char.h (limited to 'drivers/rpmsg/rpmsg_char.h') diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h new file mode 100644 index 000000000..117d9cbc5 --- /dev/null +++ b/drivers/rpmsg/rpmsg_char.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2022, STMicroelectronics + */ + +#ifndef __RPMSG_CHRDEV_H__ +#define __RPMSG_CHRDEV_H__ + +#if IS_ENABLED(CONFIG_RPMSG_CHAR) +/** + * rpmsg_chrdev_eptdev_create() - register char device based on an endpoint + * @rpdev: prepared rpdev to be used for creating endpoints + * @parent: parent device + * @chinfo: associated endpoint channel information. + * + * This function create a new rpmsg char endpoint device to instantiate a new + * endpoint based on chinfo information. + */ +int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, + struct rpmsg_channel_info chinfo); + +/** + * rpmsg_chrdev_eptdev_destroy() - destroy created char device endpoint. + * @data: private data associated to the endpoint device + * + * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL + * control. + */ +int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data); + +#else /*IS_ENABLED(CONFIG_RPMSG_CHAR) */ + +static inline int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, + struct rpmsg_channel_info chinfo) +{ + return -ENXIO; +} + +static inline int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) +{ + return -ENXIO; +} + +#endif /*IS_ENABLED(CONFIG_RPMSG_CHAR) */ + +#endif /*__RPMSG_CHRDEV_H__ */ -- cgit v1.3.1