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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24B18C2D0CE for ; Tue, 21 Jan 2020 12:49:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EEC522064C for ; Tue, 21 Jan 2020 12:49:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727962AbgAUMta (ORCPT ); Tue, 21 Jan 2020 07:49:30 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:57296 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726968AbgAUMt3 (ORCPT ); Tue, 21 Jan 2020 07:49:29 -0500 Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 14596C7C8A9241831D23; Tue, 21 Jan 2020 20:49:27 +0800 (CST) Received: from huawei.com (10.175.124.28) by DGGEMS412-HUB.china.huawei.com (10.3.19.212) with Microsoft SMTP Server id 14.3.439.0; Tue, 21 Jan 2020 20:49:16 +0800 From: Sun Ke To: , , , CC: , , Subject: [PATCH] nbd: add a flush_workqueue in nbd_start_device Date: Tue, 21 Jan 2020 20:48:13 +0800 Message-ID: <20200121124813.13332-1-sunke32@huawei.com> X-Mailer: git-send-email 2.17.2 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.124.28] X-CFilter-Loop: Reflected Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org When kzalloc fail, may cause trying to destroy the workqueue from inside the workqueue. If num_connections is m (2 < m), and NO.1 ~ NO.n (1 < n < m) kzalloc are successful. The NO.(n + 1) failed. Then, nbd_start_device will return ENOMEM to nbd_start_device_ioctl, and nbd_start_device_ioctl will return immediately without running flush_workqueue. However, we still have n recv threads. If nbd_release run first, recv threads may have to drop the last config_refs and try to destroy the workqueue from inside the workqueue. To fix it, add a flush_workqueue in nbd_start_device. Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Signed-off-by: Sun Ke --- drivers/block/nbd.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index b4607dd96185..dd1f8c2c6169 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1264,7 +1264,12 @@ static int nbd_start_device(struct nbd_device *nbd) args = kzalloc(sizeof(*args), GFP_KERNEL); if (!args) { - sock_shutdown(nbd); + if (i == 0) + sock_shutdown(nbd); + else { + sock_shutdown(nbd); + flush_workqueue(nbd->recv_workq); + } return -ENOMEM; } sk_set_memalloc(config->socks[i]->sock->sk); -- 2.17.2