io_uring: cancel work if task_work_add() fails (e3aabf95) · Commits · 戴 / test

We currently move it to the io_wqe_manager for execution, but we cannot safely do so as we may lack some of the state to execute it out of context. As we cancel work anyway when the ring/task exits, just mark this request as canceled and io_async_task_func() will do the right thing. Fixes: ("io_uring: use io-wq manager as backup task if task is exiting") Signed-off-by:

Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -4135,12 +4135,14 @@ static int __io_async_wake(struct io_kiocb req, struct io_poll_iocb poll,
		req->result = mask;
		init_task_work(&req->task_work, func);
		/*
		* If this fails, then the task is exiting. Punt to one of the io-wq
		* threads to ensure the work gets run, we can't always rely on exit
		* cancelation taking care of this.
		* If this fails, then the task is exiting. When a task exits, the
		* work gets canceled, so just cancel this request as well instead
		* of executing it. We can't safely execute it anyway, as we may not
		* have the needed state needed for it anyway.
		*/
		ret = task_work_add(tsk, &req->task_work, true);
		if (unlikely(ret)) {
		WRITE_ONCE(poll->canceled, true);
		tsk = io_wq_get_task(req->ctx->io_wq);
		task_work_add(tsk, &req->task_work, true);
		}

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