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 --- fs/btrfs/async-thread.h | 51 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 fs/btrfs/async-thread.h (limited to 'fs/btrfs/async-thread.h') diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h new file mode 100644 index 000000000..04c2f3175 --- /dev/null +++ b/fs/btrfs/async-thread.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * Copyright (C) 2014 Fujitsu. All rights reserved. + */ + +#ifndef BTRFS_ASYNC_THREAD_H +#define BTRFS_ASYNC_THREAD_H + +#include +#include +#include + +struct btrfs_fs_info; +struct btrfs_workqueue; +struct btrfs_work; + +typedef void (*btrfs_func_t)(struct btrfs_work *arg); +typedef void (*btrfs_ordered_func_t)(struct btrfs_work *arg, bool); + +struct btrfs_work { + btrfs_func_t func; + btrfs_ordered_func_t ordered_func; + + /* Don't touch things below */ + struct work_struct normal_work; + struct list_head ordered_list; + struct btrfs_workqueue *wq; + unsigned long flags; +}; + +struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info, + const char *name, + unsigned int flags, + int limit_active, + int thresh); +struct btrfs_workqueue *btrfs_alloc_ordered_workqueue( + struct btrfs_fs_info *fs_info, const char *name, + unsigned int flags); +void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func, + btrfs_ordered_func_t ordered_func); +void btrfs_queue_work(struct btrfs_workqueue *wq, + struct btrfs_work *work); +void btrfs_destroy_workqueue(struct btrfs_workqueue *wq); +void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max); +struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work); +struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct btrfs_workqueue *wq); +bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq); +void btrfs_flush_workqueue(struct btrfs_workqueue *wq); + +#endif -- cgit v1.3.1