From patchwork Wed May 18 12:26:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12853587 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 DCEFBC43217 for ; Wed, 18 May 2022 12:12:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236260AbiERMMx (ORCPT ); Wed, 18 May 2022 08:12:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236268AbiERMMt (ORCPT ); Wed, 18 May 2022 08:12:49 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 55A9E14B67E; Wed, 18 May 2022 05:12:40 -0700 (PDT) Received: from kwepemi100017.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L3Bg856V3zhZ9t; Wed, 18 May 2022 20:11:48 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100017.china.huawei.com (7.221.188.163) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 18 May 2022 20:12:38 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 18 May 2022 20:12:37 +0800 From: Yu Kuai To: , , CC: , , , , Subject: [PATCH -next v2 4/6] nbd: fix io hung while disconnecting device Date: Wed, 18 May 2022 20:26:16 +0800 Message-ID: <20220518122618.1702997-5-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220518122618.1702997-1-yukuai3@huawei.com> References: <20220518122618.1702997-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org In our tests, "qemu-nbd" triggers a io hung: INFO: task qemu-nbd:11445 blocked for more than 368 seconds. Not tainted 5.18.0-rc3-next-20220422-00003-g2176915513ca #884 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:qemu-nbd state:D stack: 0 pid:11445 ppid: 1 flags:0x00000000 Call Trace: __schedule+0x480/0x1050 ? _raw_spin_lock_irqsave+0x3e/0xb0 schedule+0x9c/0x1b0 blk_mq_freeze_queue_wait+0x9d/0xf0 ? ipi_rseq+0x70/0x70 blk_mq_freeze_queue+0x2b/0x40 nbd_add_socket+0x6b/0x270 [nbd] nbd_ioctl+0x383/0x510 [nbd] blkdev_ioctl+0x18e/0x3e0 __x64_sys_ioctl+0xac/0x120 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fd8ff706577 RSP: 002b:00007fd8fcdfebf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000040000000 RCX: 00007fd8ff706577 RDX: 000000000000000d RSI: 000000000000ab00 RDI: 000000000000000f RBP: 000000000000000f R08: 000000000000fbe8 R09: 000055fe497c62b0 R10: 00000002aff20000 R11: 0000000000000246 R12: 000000000000006d R13: 0000000000000000 R14: 00007ffe82dc5e70 R15: 00007fd8fcdff9c0 "qemu-ndb -d" will call ioctl 'NBD_DISCONNECT' first, however, following message was found: block nbd0: Send disconnect failed -32 Which indicate that something is wrong with the server. Then, "qemu-nbd -d" will call ioctl 'NBD_CLEAR_SOCK', however ioctl can't clear requests after commit 2516ab1543fd("nbd: only clear the queue on device teardown"). And in the meantime, request can't complete through timeout because nbd_xmit_timeout() will always return 'BLK_EH_RESET_TIMER', which means such request will never be completed in this situation. Now that the flag 'NBD_CMD_INFLIGHT' can make sure requests won't complete multiple times, switch back to call nbd_clear_sock() in nbd_clear_sock_ioctl(), so that inflight requests can be cleared. Signed-off-by: Yu Kuai --- drivers/block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index a0d0910dae2a..ec736cc52134 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1429,7 +1429,7 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd) static void nbd_clear_sock_ioctl(struct nbd_device *nbd, struct block_device *bdev) { - sock_shutdown(nbd); + nbd_clear_sock(nbd); __invalidate_device(bdev, true); nbd_bdev_reset(nbd); if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,