From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>, io-uring <[email protected]>
Subject: Re: [PATCH v2] io_uring/net: ensure async prep handlers always initialize ->done_io
Date: Fri, 15 Mar 2024 23:13:04 +0000 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 3/15/24 23:09, Pavel Begunkov wrote:
> On 3/15/24 22:48, Jens Axboe wrote:
>> If we get a request with IOSQE_ASYNC set, then we first run the prep
>> async handlers. But if we then fail setting it up and want to post
>> a CQE with -EINVAL, we use ->done_io. This was previously guarded with
>> REQ_F_PARTIAL_IO, and the normal setup handlers do set it up before any
>> potential errors, but we need to cover the async setup too.
>
> You can hit io_req_defer_failed() { opdef->fail(); }
> off of an early submission failure path where def->prep has
> not yet been called, I don't think the patch will fix the
> problem.
>
> ->fail() handlers are fragile, maybe we should skip them
> if def->prep() wasn't called. Not even compile tested:
>
>
> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
> index 846d67a9c72e..56eed1490571 100644
> --- a/io_uring/io_uring.c
> +++ b/io_uring/io_uring.c
> @@ -993,7 +993,7 @@ void io_req_defer_failed(struct io_kiocb *req, s32 res)
>
> req_set_fail(req);
> io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
> - if (def->fail)
> + if ((req->flags & REQ_F_EARLY_FAIL) && def->fail)
it rather should've been
!(req->flags & REQ_F_EARLY_FAIL)
> def->fail(req);
> io_req_complete_defer(req);
> }
> @@ -2201,8 +2201,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
> }
> req->flags |= REQ_F_CREDS;
> }
> -
> - return def->prep(req, sqe);
> + return 0;
> }
>
> static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
> @@ -2250,8 +2249,15 @@ static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
> int ret;
>
> ret = io_init_req(ctx, req, sqe);
> - if (unlikely(ret))
> + if (unlikely(ret)) {
> +fail:
> + req->flags |= REQ_F_EARLY_FAIL;
> return io_submit_fail_init(sqe, req, ret);
> + }
> +
> + ret = def->prep(req, sqe);
> + if (unlikely(ret))
> + goto fail;
>
> trace_io_uring_submit_req(req);
>
--
Pavel Begunkov
next prev parent reply other threads:[~2024-03-15 23:14 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-15 22:48 [PATCH v2] io_uring/net: ensure async prep handlers always initialize ->done_io Jens Axboe
2024-03-15 23:09 ` Pavel Begunkov
2024-03-15 23:13 ` Pavel Begunkov [this message]
2024-03-15 23:19 ` Pavel Begunkov
2024-03-15 23:25 ` Jens Axboe
2024-03-15 23:28 ` Pavel Begunkov
2024-03-15 23:53 ` Jens Axboe
2024-03-16 16:14 ` Jens Axboe
2024-03-16 16:28 ` Pavel Begunkov
2024-03-16 16:31 ` Jens Axboe
2024-03-16 16:32 ` Pavel Begunkov
2024-03-16 16:34 ` Pavel Begunkov
2024-03-16 16:36 ` Jens Axboe
2024-03-16 16:36 ` Pavel Begunkov
2024-03-16 16:40 ` Pavel Begunkov
2024-03-16 16:42 ` Jens Axboe
2024-03-16 16:46 ` Pavel Begunkov
2024-03-16 16:51 ` Jens Axboe
2024-03-16 16:57 ` Pavel Begunkov
2024-03-16 17:01 ` Jens Axboe
2024-03-16 17:42 ` Pavel Begunkov
2024-03-16 23:58 ` Jens Axboe
2024-03-17 20:45 ` Pavel Begunkov
2024-03-15 23:13 ` Jens Axboe
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