From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 322A1C004D4 for ; Thu, 19 Jan 2023 17:33:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229503AbjASRdR (ORCPT ); Thu, 19 Jan 2023 12:33:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229688AbjASRdQ (ORCPT ); Thu, 19 Jan 2023 12:33:16 -0500 Received: from mail-wm1-x32a.google.com (mail-wm1-x32a.google.com [IPv6:2a00:1450:4864:20::32a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABE1E5593 for ; Thu, 19 Jan 2023 09:33:14 -0800 (PST) Received: by mail-wm1-x32a.google.com with SMTP id d4-20020a05600c3ac400b003db1de2aef0so1821088wms.2 for ; Thu, 19 Jan 2023 09:33:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=99ojboZnNmPKgHgXG5Pa4m8j6QglL+OzQRGBJ/Nx/TU=; b=R/zpBd3pxGFNMpM+m35rLI7bYbcmlknNZz3lqxVFlmHCSRE6f6JJ+QJHayDaGtFibD pRkL9fZ5wUtAe2gCNsd1q+VqEcwMqpWs6oG0yLpc7O/6MqC7n+YJUBa6XuONuqmGCFIk fQAXJN8chEmXmDYNpgZGigHC3C7cjSWahhb3PBmaJ2oKExFMMK2/Mq4dFCfdU5FV6RUb 2kEym8zz44euxrpqKRaa1Hz5rikINDjs4D1Rc+v/ar+j3Uvt2UhrIa6Ez/w1Hn2WwoJa NbJJtMRZjzq0Q2Q4DjHv+PJjhRsfYoSLQ1DB3wUsZdLs2yeFSdYE0xlZjLcwHE5/XsjS k7Jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=99ojboZnNmPKgHgXG5Pa4m8j6QglL+OzQRGBJ/Nx/TU=; b=KKZtCkxhv/l3K9mp909FmuV8jEr1RLkCnWYR39wdBozluKNkd3O0C7GsYvEKsYGghD M82wdi5vx7P/YJ1ayNNWGRNXAopLE33SNZBgjyHxPiEdD+bVJ6miAkB8iYBBYymuusLr OJDBTMP5mjnKv+C2gHu7hvKHItH1jkpu2M3CxlFK6nUlZihHcytx/4Bpi0+q150zDOqF pqRGWhxZWpnXBhF1EvK4Aj4taEXwUVwaYtpO7Ykr1n9KXnRkDMUs/TidutJjzobiWMsk l3hNCcx3B/QF4igBhDS1yRRs2rxijncg8AgVDmY4OR8XuxeoBDTS9eZ2aVALb2oYX9iD ykOw== X-Gm-Message-State: AFqh2kqzNQOzKt6HE0nOud1Jz5tl7PJ3iefjlh7IREP8xEYIg2KT4LhF Ld/GOt9aNRIJtzuPjlkFb5elYYKG7Z4= X-Google-Smtp-Source: AMrXdXs2Wrx3J6lRVzdNoIzco/ycNXn5Yq3CcvQlH4YNRIstHodOMVJI+XmEHh0hlXu1UF4JkRVW7Q== X-Received: by 2002:a05:600c:3ac8:b0:3da:270b:ba6b with SMTP id d8-20020a05600c3ac800b003da270bba6bmr11533356wms.41.1674149592992; Thu, 19 Jan 2023 09:33:12 -0800 (PST) Received: from [192.168.8.100] (188.30.84.186.threembb.co.uk. [188.30.84.186]) by smtp.gmail.com with ESMTPSA id i16-20020a1c5410000000b003db01178b62sm5450573wmb.40.2023.01.19.09.33.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 19 Jan 2023 09:33:12 -0800 (PST) Message-ID: Date: Thu, 19 Jan 2023 17:31:00 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.1 Subject: Re: WARNING in io_fill_cqe_aux To: Jens Axboe , Xingyuan Mo Cc: syzkaller@googlegroups.com, io-uring@vger.kernel.org References: <6b21328e-d32c-3a54-0578-7a39412d4615@kernel.dk> Content-Language: en-US From: Pavel Begunkov In-Reply-To: <6b21328e-d32c-3a54-0578-7a39412d4615@kernel.dk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 1/19/23 15:54, Jens Axboe wrote: > On 1/19/23 4:37?AM, Xingyuan Mo wrote: >> Hello, >> >> Recently, when using our tool to fuzz kernel, the following bug was >> triggered. >> >> HEAD commit: 5dc4c995db9e Linux 6.2-rc4 >> git tree: mainline >> compiler: gcc (Ubuntu 10.3.0-1ubuntu1~20.04) 10.3.0 >> kernel config: https://drive.google.com/file/d/1anGeZxcTgSKNZX4oywvsSfLqw1tcZSTp/view?usp=share_link >> C reproducer: https://drive.google.com/file/d/1DxYuWGnFSBhqve-jjXloYhwKpyUm8nDt/view?usp=share_link >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: Xingyuan Mo >> >> ------------[ cut here ]------------ >> WARNING: CPU: 1 PID: 36200 at io_uring/io_uring.h:108 io_get_cqe_overflow root/linux-6.2-rc4/io_uring/io_uring.h:108 [inline] >> WARNING: CPU: 1 PID: 36200 at io_uring/io_uring.h:108 io_get_cqe root/linux-6.2-rc4/io_uring/io_uring.h:125 [inline] >> WARNING: CPU: 1 PID: 36200 at io_uring/io_uring.h:108 io_fill_cqe_aux+0x69b/0x840 root/linux-6.2-rc4/io_uring/io_uring.c:832 >> Modules linked in: >> CPU: 1 PID: 36200 Comm: syz-executor.0 Not tainted 6.2.0-rc4 #1 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 >> RIP: 0010:io_get_cqe_overflow root/linux-6.2-rc4/io_uring/io_uring.h:108 [inline] >> RIP: 0010:io_get_cqe root/linux-6.2-rc4/io_uring/io_uring.h:125 [inline] >> RIP: 0010:io_fill_cqe_aux+0x69b/0x840 root/linux-6.2-rc4/io_uring/io_uring.c:832 >> Code: fd 48 8d bb a8 00 00 00 be ff ff ff ff e8 dd 1b 02 06 31 ff 89 c5 89 c6 e8 c2 76 7e fd 85 ed 0f 85 44 fa ff ff e8 05 7a 7e fd <0f> 0b e9 38 fa ff ff e8 f9 79 7e fd 31 ff 89 ee e8 a0 76 7e fd 85 >> RSP: 0018:ffffc90015747b68 EFLAGS: 00010212 >> RAX: 000000000000016e RBX: ffff8881245b6000 RCX: ffffc90013881000 >> RDX: 0000000000040000 RSI: ffffffff8401f31b RDI: 0000000000000005 >> RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 >> R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881245b6018 >> FS: 00007fcf02ab4700(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 0000001b2e024000 CR3: 00000001054e6000 CR4: 0000000000752ee0 >> PKRU: 55555554 >> Call Trace: >> >> __io_post_aux_cqe root/linux-6.2-rc4/io_uring/io_uring.c:880 [inline] >> io_post_aux_cqe+0x3b/0x90 root/linux-6.2-rc4/io_uring/io_uring.c:890 >> io_msg_ring_data root/linux-6.2-rc4/io_uring/msg_ring.c:74 [inline] >> io_msg_ring+0x5b9/0xb70 root/linux-6.2-rc4/io_uring/msg_ring.c:227 >> io_issue_sqe+0x6c2/0x1210 root/linux-6.2-rc4/io_uring/io_uring.c:1856 >> io_queue_sqe root/linux-6.2-rc4/io_uring/io_uring.c:2028 [inline] >> io_submit_sqe root/linux-6.2-rc4/io_uring/io_uring.c:2286 [inline] >> io_submit_sqes+0x96c/0x1e10 root/linux-6.2-rc4/io_uring/io_uring.c:2397 >> __do_sys_io_uring_enter+0xc20/0x2540 root/linux-6.2-rc4/io_uring/io_uring.c:3345 >> do_syscall_x64 root/linux-6.2-rc4/arch/x86/entry/common.c:50 [inline] >> do_syscall_64+0x39/0xb0 root/linux-6.2-rc4/arch/x86/entry/common.c:80 >> entry_SYSCALL_64_after_hwframe+0x63/0xcd >> RIP: 0033:0x7fcf01c8f6cd >> Code: c3 e8 17 32 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 >> RSP: 002b:00007fcf02ab3bf8 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa >> RAX: ffffffffffffffda RBX: 00007fcf01dbbf80 RCX: 00007fcf01c8f6cd >> RDX: 0000000000000000 RSI: 0000000000007b84 RDI: 0000000000000004 >> RBP: 00007fcf01cfcb05 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 >> R13: 00007fcf01edfb2f R14: 00007fcf01edfcd0 R15: 00007fcf02ab3d80 >> > > I think this should fix it. Pavel? Looking that you added uring_lock locking, was the target ring IOPOLL? If so sounds right and a comment below > diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c > index 2d3cd945a531..c98e9c74054b 100644 > --- a/io_uring/msg_ring.c > +++ b/io_uring/msg_ring.c [...] > + > void io_msg_ring_cleanup(struct io_kiocb *req) > { > struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); > @@ -43,20 +65,25 @@ static void io_msg_tw_complete(struct callback_head *head) > struct io_ring_ctx *target_ctx = req->file->private_data; > int ret = 0; > > - if (current->flags & PF_EXITING) > + if (current->flags & PF_EXITING) { > ret = -EOWNERDEAD; > - else if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0)) > - ret = -EOVERFLOW; > + } else { > + mutex_lock(&target_ctx->uring_lock); It can be be conditional or could use a comment that it's only necessary in case of IOPOLL ring. > + if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0)) > + ret = -EOVERFLOW; > + mutex_unlock(&target_ctx->uring_lock); > + } > > if (ret < 0) > req_set_fail(req); > io_req_queue_tw_complete(req, ret); > } > -- Pavel Begunkov