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[86.62.88.107]) by smtp.gmail.com with ESMTPSA id s12sm2240202ljd.116.2020.08.15.00.47.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 15 Aug 2020 00:47:42 -0700 (PDT) To: Jens Axboe , Josef , io-uring@vger.kernel.org Cc: norman@apache.org References: <8e734ada-7f28-22df-5f30-027aca3695d1@gmail.com> <5fa9e01f-137d-b0f8-211a-975c7ed56419@gmail.com> From: Pavel Begunkov Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Subject: Re: io_uring process termination/killing is not working Message-ID: Date: Sat, 15 Aug 2020 10:45:36 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 13/08/2020 02:32, Jens Axboe wrote: > On 8/12/20 12:28 PM, Pavel Begunkov wrote: >> On 12/08/2020 21:22, Pavel Begunkov wrote: >>> On 12/08/2020 21:20, Pavel Begunkov wrote: >>>> On 12/08/2020 21:05, Jens Axboe wrote: >>>>> On 8/12/20 11:58 AM, Josef wrote: >>>>>> Hi, >>>>>> >>>>>> I have a weird issue on kernel 5.8.0/5.8.1, SIGINT even SIGKILL >>>>>> doesn't work to kill this process(always state D or D+), literally I >>>>>> have to terminate my VM because even the kernel can't kill the process >>>>>> and no issue on 5.7.12-201, however if IOSQE_IO_LINK is not set, it >>>>>> works >>>>>> >>>>>> I've attached a file to reproduce it >>>>>> or here >>>>>> https://gist.github.com/1Jo1/15cb3c63439d0c08e3589cfa98418b2c >>>>> >>>>> Thanks, I'll take a look at this. It's stuck in uninterruptible >>>>> state, which is why you can't kill it. >>>> >>>> It looks like one of the hangs I've been talking about a few days ago, >>>> an accept is inflight but can't be found by cancel_files() because it's >>>> in a link. >>> >>> BTW, I described it a month ago, there were more details. >> >> https://lore.kernel.org/io-uring/34eb5e5a-8d37-0cae-be6c-c6ac4d85b5d4@gmail.com > > Yeah I think you're right. How about something like the below? That'll > potentially cancel more than just the one we're looking for, but seems > kind of silly to only cancel from the file table holding request and to > the end. The bug is not poll/t-out related, IIRC my test reproduces it with read(pipe)->open(). See the previously sent link. As mentioned, I'm going to patch that up, if you won't beat me on that. > > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index 8a2afd8c33c9..0630a9622baa 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -4937,6 +5003,7 @@ static bool io_poll_remove_one(struct io_kiocb *req) > io_cqring_fill_event(req, -ECANCELED); > io_commit_cqring(req->ctx); > req->flags |= REQ_F_COMP_LOCKED; > + req_set_fail_links(req); > io_put_req(req); > } > > @@ -7935,6 +8002,47 @@ static bool io_wq_files_match(struct io_wq_work *work, void *data) > return work->files == files; > } > > +static bool __io_poll_remove_link(struct io_kiocb *preq, struct io_kiocb *req) > +{ > + struct io_kiocb *link; > + > + if (!(preq->flags & REQ_F_LINK_HEAD)) > + return false; > + > + list_for_each_entry(link, &preq->link_list, link_list) { > + if (link != req) > + break; > + io_poll_remove_one(preq); > + return true; > + } > + > + return false; > +} > + > +/* > + * We're looking to cancel 'req' because it's holding on to our files, but > + * 'req' could be a link to another request. See if it is, and cancel that > + * parent request if so. > + */ > +static void io_poll_remove_link(struct io_ring_ctx *ctx, struct io_kiocb *req) > +{ > + struct hlist_node *tmp; > + struct io_kiocb *preq; > + int i; > + > + spin_lock_irq(&ctx->completion_lock); > + for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { > + struct hlist_head *list; > + > + list = &ctx->cancel_hash[i]; > + hlist_for_each_entry_safe(preq, tmp, list, hash_node) { > + if (__io_poll_remove_link(preq, req)) > + break; > + } > + } > + spin_unlock_irq(&ctx->completion_lock); > +} > + > static void io_uring_cancel_files(struct io_ring_ctx *ctx, > struct files_struct *files) > { > @@ -7989,6 +8097,8 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx, > } > } else { > io_wq_cancel_work(ctx->io_wq, &cancel_req->work); > + /* could be a link, check and remove if it is */ > + io_poll_remove_link(ctx, cancel_req); > io_put_req(cancel_req); > } > > -- Pavel Begunkov