linux-kernel - [PATCH 1/1] io_uring: fix lazy work init

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Message-Id: <a75c1537cc655cb766e8e2517e18f74e13d60f1b.1592228129.git.asml.silence@gmail.com>
Date:   Mon, 15 Jun 2020 16:36:30 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Jens Axboe <axboe@...nel.dk>, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     jiufei.xue@...ux.alibaba.com
Subject: [PATCH 1/1] 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@...il.com>
---
 fs/io_uring.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 54addaba742d..410b2df16c71 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1105,6 +1105,7 @@ 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);
-- 
2.24.0