io_uring: fix lazy work init

Don't leave garbage in req.work before punting async on -EAGAIN
in io_iopoll_queue().

[  140.922099] general protection fault, probably for non-canonical
     address 0xdead000000000100: 0000 [#1] PREEMPT SMP PTI
...
[  140.922105] RIP: 0010:io_worker_handle_work+0x1db/0x480
...
[  140.922114] Call Trace:
[  140.922118]  ? __next_timer_interrupt+0xe0/0xe0
[  140.922119]  io_wqe_worker+0x2a9/0x360
[  140.922121]  ? _raw_spin_unlock_irqrestore+0x24/0x40
[  140.922124]  kthread+0x12c/0x170
[  140.922125]  ? io_worker_handle_work+0x480/0x480
[  140.922126]  ? kthread_park+0x90/0x90
[  140.922127]  ret_from_fork+0x22/0x30

Fixes: 7cdaf587de7c ("io_uring: avoid whole io_wq_work copy for requests completed inline")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 155f3d830ddb36bf7894d606bcb6ed58fafa0676..c04b20bf28039be8c02999e70fe22281f583d4d2 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1087,6 +1087,7 @@ static inline void io_prep_async_work(struct io_kiocb *req,
                        req->work.flags |= IO_WQ_WORK_UNBOUND;
        }
 
+       io_req_init_async(req);
        io_req_work_grab_env(req, def);
 
        *link = io_prep_linked_timeout(req);