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 --- io_uring/sync.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 io_uring/sync.c (limited to 'io_uring/sync.c') diff --git a/io_uring/sync.c b/io_uring/sync.c new file mode 100644 index 000000000..ab7fa1cd7 --- /dev/null +++ b/io_uring/sync.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "io_uring.h" +#include "sync.h" + +struct io_sync { + struct file *file; + loff_t len; + loff_t off; + int flags; + int mode; +}; + +int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync); + + if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in)) + return -EINVAL; + + sync->off = READ_ONCE(sqe->off); + sync->len = READ_ONCE(sqe->len); + sync->flags = READ_ONCE(sqe->sync_range_flags); + req->flags |= REQ_F_FORCE_ASYNC; + + return 0; +} + +int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync); + int ret; + + /* sync_file_range always requires a blocking context */ + WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK); + + ret = sync_file_range(req->file, sync->off, sync->len, sync->flags); + io_req_set_res(req, ret, 0); + return IOU_COMPLETE; +} + +int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync); + + if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in)) + return -EINVAL; + + sync->flags = READ_ONCE(sqe->fsync_flags); + if (unlikely(sync->flags & ~IORING_FSYNC_DATASYNC)) + return -EINVAL; + + sync->off = READ_ONCE(sqe->off); + if (sync->off < 0) + return -EINVAL; + sync->len = READ_ONCE(sqe->len); + req->flags |= REQ_F_FORCE_ASYNC; + return 0; +} + +int io_fsync(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync); + loff_t end = sync->off + sync->len; + int ret; + + /* fsync always requires a blocking context */ + WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK); + + ret = vfs_fsync_range(req->file, sync->off, end > 0 ? end : LLONG_MAX, + sync->flags & IORING_FSYNC_DATASYNC); + io_req_set_res(req, ret, 0); + return IOU_COMPLETE; +} + +int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync); + + if (sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in) + return -EINVAL; + + sync->off = READ_ONCE(sqe->off); + sync->len = READ_ONCE(sqe->addr); + sync->mode = READ_ONCE(sqe->len); + req->flags |= REQ_F_FORCE_ASYNC; + return 0; +} + +int io_fallocate(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync); + int ret; + + /* fallocate always requiring blocking context */ + WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK); + + ret = vfs_fallocate(req->file, sync->mode, sync->off, sync->len); + if (ret >= 0) + fsnotify_modify(req->file); + io_req_set_res(req, ret, 0); + return IOU_COMPLETE; +} -- cgit v1.3.1