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/truncate.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 io_uring/truncate.c (limited to 'io_uring/truncate.c') diff --git a/io_uring/truncate.c b/io_uring/truncate.c new file mode 100644 index 000000000..c88d8bd8d --- /dev/null +++ b/io_uring/truncate.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "../fs/internal.h" + +#include "io_uring.h" +#include "truncate.h" + +struct io_ftrunc { + struct file *file; + loff_t len; +}; + +int io_ftruncate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_ftrunc *ft = io_kiocb_to_cmd(req, struct io_ftrunc); + + if (sqe->rw_flags || sqe->addr || sqe->len || sqe->buf_index || + sqe->splice_fd_in || sqe->addr3) + return -EINVAL; + + ft->len = READ_ONCE(sqe->off); + + req->flags |= REQ_F_FORCE_ASYNC; + return 0; +} + +int io_ftruncate(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_ftrunc *ft = io_kiocb_to_cmd(req, struct io_ftrunc); + int ret; + + WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK); + + ret = do_ftruncate(req->file, ft->len, 0); + + io_req_set_res(req, ret, 0); + return IOU_COMPLETE; +} -- cgit v1.3.1