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Thu, 06 Feb 2020 09:05:15 -0800 (PST) Subject: Re: [PATCH] io_uring: fix deferred req iovec leak From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: 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== Message-ID: Date: Thu, 6 Feb 2020 20:04:23 +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: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="5zeWxke3G80bhc4BcfV4EXz6mBjNssYbV" Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --5zeWxke3G80bhc4BcfV4EXz6mBjNssYbV Content-Type: multipart/mixed; boundary="soFEx96mETQcmOIihqrtFN2p8r3OXDPvN"; protected-headers="v1" From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: Subject: Re: [PATCH] io_uring: fix deferred req iovec leak References: In-Reply-To: --soFEx96mETQcmOIihqrtFN2p8r3OXDPvN Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 06/02/2020 19:51, Pavel Begunkov wrote: > After defer, a request will be prepared, that includes allocating iovec= > if needed, and then submitted through io_wq_submit_work() but not custo= m > handler (e.g. io_rw_async()/io_sendrecv_async()). However, it'll leak > iovec, as it's in io-wq and the code goes as follows: >=20 > io_read() { > if (!io_wq_current_is_worker()) > kfree(iovec); > } >=20 > Put all deallocation logic in io_{read,write,send,recv}(), which will > leave the memory, if going async with -EAGAIN. >=20 Interestingly, this will fail badly if it returns -EAGAIN from io-wq cont= ext. Apparently, I need to do v2. > It also fixes a leak after failed io_alloc_async_ctx() in > io_{recv,send}_msg(). >=20 > Signed-off-by: Pavel Begunkov > --- > fs/io_uring.c | 47 ++++++++++++----------------------------------- > 1 file changed, 12 insertions(+), 35 deletions(-) >=20 > diff --git a/fs/io_uring.c b/fs/io_uring.c > index bff7a03e873f..ce3dbd2b1b5c 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -2143,17 +2143,6 @@ static int io_alloc_async_ctx(struct io_kiocb *r= eq) > return req->io =3D=3D NULL; > } > =20 > -static void io_rw_async(struct io_wq_work **workptr) > -{ > - struct io_kiocb *req =3D container_of(*workptr, struct io_kiocb, work= ); > - struct iovec *iov =3D NULL; > - > - if (req->io->rw.iov !=3D req->io->rw.fast_iov) > - iov =3D req->io->rw.iov; > - io_wq_submit_work(workptr); > - kfree(iov); > -} > - > static int io_setup_async_rw(struct io_kiocb *req, ssize_t io_size, > struct iovec *iovec, struct iovec *fast_iov, > struct iov_iter *iter) > @@ -2166,7 +2155,6 @@ static int io_setup_async_rw(struct io_kiocb *req= , ssize_t io_size, > =20 > io_req_map_rw(req, io_size, iovec, fast_iov, iter); > } > - req->work.func =3D io_rw_async; > return 0; > } > =20 > @@ -2253,8 +2241,7 @@ static int io_read(struct io_kiocb *req, struct i= o_kiocb **nxt, > } > } > out_free: > - if (!io_wq_current_is_worker()) > - kfree(iovec); > + kfree(iovec); > return ret; > } > =20 > @@ -2359,8 +2346,7 @@ static int io_write(struct io_kiocb *req, struct = io_kiocb **nxt, > } > } > out_free: > - if (!io_wq_current_is_worker()) > - kfree(iovec); > + kfree(iovec); > return ret; > } > =20 > @@ -2955,19 +2941,6 @@ static int io_sync_file_range(struct io_kiocb *r= eq, struct io_kiocb **nxt, > return 0; > } > =20 > -#if defined(CONFIG_NET) > -static void io_sendrecv_async(struct io_wq_work **workptr) > -{ > - struct io_kiocb *req =3D container_of(*workptr, struct io_kiocb, work= ); > - struct iovec *iov =3D NULL; > - > - if (req->io->rw.iov !=3D req->io->rw.fast_iov) > - iov =3D req->io->msg.iov; > - io_wq_submit_work(workptr); > - kfree(iov); > -} > -#endif > - > static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring= _sqe *sqe) > { > #if defined(CONFIG_NET) > @@ -3036,17 +3009,19 @@ static int io_sendmsg(struct io_kiocb *req, str= uct io_kiocb **nxt, > if (force_nonblock && ret =3D=3D -EAGAIN) { > if (req->io) > return -EAGAIN; > - if (io_alloc_async_ctx(req)) > + if (io_alloc_async_ctx(req)) { > + if (kmsg && kmsg->iov !=3D kmsg->fast_iov) > + kfree(kmsg->iov); > return -ENOMEM; > + } > memcpy(&req->io->msg, &io.msg, sizeof(io.msg)); > - req->work.func =3D io_sendrecv_async; > return -EAGAIN; > } > if (ret =3D=3D -ERESTARTSYS) > ret =3D -EINTR; > } > =20 > - if (!io_wq_current_is_worker() && kmsg && kmsg->iov !=3D kmsg->fast_i= ov) > + if (kmsg && kmsg->iov !=3D kmsg->fast_iov) > kfree(kmsg->iov); > io_cqring_add_event(req, ret); > if (ret < 0) > @@ -3180,17 +3155,19 @@ static int io_recvmsg(struct io_kiocb *req, str= uct io_kiocb **nxt, > if (force_nonblock && ret =3D=3D -EAGAIN) { > if (req->io) > return -EAGAIN; > - if (io_alloc_async_ctx(req)) > + if (io_alloc_async_ctx(req)) { > + if (kmsg && kmsg->iov !=3D kmsg->fast_iov) > + kfree(kmsg->iov); > return -ENOMEM; > + } > memcpy(&req->io->msg, &io.msg, sizeof(io.msg)); > - req->work.func =3D io_sendrecv_async; > return -EAGAIN; > } > if (ret =3D=3D -ERESTARTSYS) > ret =3D -EINTR; > } > =20 > - if (!io_wq_current_is_worker() && kmsg && kmsg->iov !=3D kmsg->fast_i= ov) > + if (kmsg && kmsg->iov !=3D kmsg->fast_iov) > kfree(kmsg->iov); > io_cqring_add_event(req, ret); > if (ret < 0) >=20 --=20 Pavel Begunkov --soFEx96mETQcmOIihqrtFN2p8r3OXDPvN-- --5zeWxke3G80bhc4BcfV4EXz6mBjNssYbV Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+6JuPTjTbx479o3OWt5b1Glr+6UFAl48RyUACgkQWt5b1Glr +6UorhAAnUshpxCEREXrxDkh35/07TVhwYEWryJVy1bjVuV6pqHL0FWV7wh5o6NR NsRzR1N/gveg7MUaXMwQNHl0XxTvMYOt8AQu1dwnB2iR5eaKLioQ/sIOKBZuwAuu RTLdHhVGezB3eIcruwvmifBKp9KbBMsMC7P1g4Ak1HwPB/66fgMDxiA0kDcyma0H hjNm9TPylBfTG6hvokYvWdefyJgX2ZBLDXj+eiAqAV7b7Z5MruCrQH7+g9GVHrEJ aAFvUwHRZTKhNQpMXl2f/qXmbmNJGds77VKfCLQgCDuDgUwSERd5fwyiNcuujrtu KvqzXEJcWhcXE6Z8Znj49QfCyzZ8vzwGu7zXuTBt/iVdEs9LNFSHKPIVKOp/Q+JP nojYq5PIwCa75uSAUxlEt14l6QEdNT/nklCT24zcVCrdz4K0VWuo4xxGu1g0n3fn CBvClnDEQrBzNlQhsMGsdlbmpilsVuuWODLdJP+JZaxmYoCsgt8sn9UxB03rwSiu A85vtjO6maKn7YS17I2td00Q85f3JgRmG1NdBrEHXXhBx9hijmpHRQVTTvaqfkPV Jc93mNivm1LMr/4TjLCrd2GPmn91FUWUcsvoirsMPucUODKdWorOAKt5AYZehSIO 2GhKLz8neXy6eeMwLMvpr1drhaU65U6VDFNTGbS0Y/XRTe5kAqs= =ClnH -----END PGP SIGNATURE----- --5zeWxke3G80bhc4BcfV4EXz6mBjNssYbV--