Commit 8ef77766 authored Jun 27, 2020 by Pavel Begunkov Committed by Jens Axboe Jun 28, 2020

io_uring: fix req->work corruption



req->work and req->task_work are in a union, so io_req_task_queue() screws
everything that was in work. De-union them for now.

[  704.367253] BUG: unable to handle page fault for address:
	ffffffffaf7330d0
[  704.367256] #PF: supervisor write access in kernel mode
[  704.367256] #PF: error_code(0x0003) - permissions violation
[  704.367261] CPU: 6 PID: 1654 Comm: io_wqe_worker-0 Tainted: G
I       5.8.0-rc2-00038-ge28d0bdc4863-dirty #498
[  704.367265] RIP: 0010:_raw_spin_lock+0x1e/0x36
...
[  704.367276]  __alloc_fd+0x35/0x150
[  704.367279]  __get_unused_fd_flags+0x25/0x30
[  704.367280]  io_openat2+0xcb/0x1b0
[  704.367283]  io_issue_sqe+0x36a/0x1320
[  704.367294]  io_wq_submit_work+0x58/0x160
[  704.367295]  io_worker_handle_work+0x2a3/0x430
[  704.367296]  io_wqe_worker+0x2a0/0x350
[  704.367301]  kthread+0x136/0x180
[  704.367304]  ret_from_fork+0x22/0x30

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 1e16c2f9

fs/io_uring.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -668,12 +668,12 @@ struct io_kiocb {
		* restore the work, if needed.
		*/
		struct {
		struct callback_head task_work;
		struct hlist_node hash_node;
		struct async_poll *apoll;
		};
		struct io_wq_work work;
		};
		struct callback_head task_work;
		};

		#define IO_IOPOLL_BATCH 8

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