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/poll.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 io_uring/poll.h (limited to 'io_uring/poll.h') diff --git a/io_uring/poll.h b/io_uring/poll.h new file mode 100644 index 000000000..5647c5138 --- /dev/null +++ b/io_uring/poll.h @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +#define IO_POLL_ALLOC_CACHE_MAX 32 + +enum { + IO_APOLL_OK, + IO_APOLL_ABORTED, + IO_APOLL_READY +}; + +struct io_poll { + struct file *file; + struct wait_queue_head *head; + __poll_t events; + int retries; + struct wait_queue_entry wait; +}; + +struct async_poll { + struct io_poll poll; + struct io_poll *double_poll; +}; + +/* + * Must only be called inside issue_flags & IO_URING_F_MULTISHOT, or + * potentially other cases where we already "own" this poll request. + */ +static inline void io_poll_multishot_retry(struct io_kiocb *req) +{ + atomic_inc(&req->poll_refs); +} + +int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_poll_add(struct io_kiocb *req, unsigned int issue_flags); + +int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags); + +struct io_cancel_data; +int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd, + unsigned issue_flags); +int io_arm_apoll(struct io_kiocb *req, unsigned issue_flags, __poll_t mask); +int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags); +bool io_poll_remove_all(struct io_ring_ctx *ctx, struct io_uring_task *tctx, + bool cancel_all); + +void io_poll_task_func(struct io_tw_req tw_req, io_tw_token_t tw); -- cgit v1.3.1