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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no 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 E1E11C433ED for ; Wed, 14 Apr 2021 03:55:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B50B661154 for ; Wed, 14 Apr 2021 03:55:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347030AbhDND4R (ORCPT ); Tue, 13 Apr 2021 23:56:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233157AbhDND4P (ORCPT ); Tue, 13 Apr 2021 23:56:15 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02A1FC061574 for ; Tue, 13 Apr 2021 20:55:54 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id k8so13460502pgf.4 for ; Tue, 13 Apr 2021 20:55:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:mime-version :content-transfer-encoding; bh=AFWFHDUFI7Y9PY8k8BG7oxzX7QttBmdc0zzgW61jnYs=; b=myqvjuWdzKk0vpevYSXLdmUTOyFyiCsUqaLxsUnxEIYB+51maTF6Anu0owZmRwkoY7 hJtAOCTIujyivSml+Bg/mDUx6RWYCTzeyts7wM4bhoketTP6LWouS7WgdPAphinCZj5q ThiiUNb23eENsraNybXBrFzXPklwad3q23knqH84gGY/ZWVn48bgJgQtig1eqodHH29y FeXj1PdTNjrvPUBksTNO0Fum2g0gNxmyc3Oa4NZnx7/oL2Roxt9pCz6y5FPtYfoWiCuF IUC7iUWzWqplD5/ZYpUWxUpAxdScdbMoSIAjCO2PsP/l15I61NHfqayiDm7kuhhDL1ti Esjg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:mime-version :content-transfer-encoding; bh=AFWFHDUFI7Y9PY8k8BG7oxzX7QttBmdc0zzgW61jnYs=; b=pZmcLc4f0JusgGabBCvgl5YPXd7L0PAhVDmJSus0leGuc1tPjXQSZnEk4KtSo3gqPg gjT2wt2DfaYRSIJymmWDiJa8Ds/iw3KGFNM9fNsG2X2g6xodT8ZCMQHRpHPAIf9+Fjqz NqS7xpRr/sNukAD8F5yBCeheGENfdAjOeZ1o4Rr+ZiOMtuLaJ1Hjp61tT5s85hMkQ9oG J+1qJmMwY+B6nAREanHXhkxpEnBuCoYgNw2o2izuqp1Y4DJuse+7gSqDn5Z/pRATX67G kKXNZWC3F6qpS05c+yyeH5jM/M/Zkbla1PoeQM17CV0JxPlm8YXWl0uw05Wcr8XOUkZ4 7JBA== X-Gm-Message-State: AOAM533fjWoI4njLskDUA7wjsPMRGEIpVmGE1q5MpoUkxKzYNcqR8NWq dxV7AW1FQOxHfxBpo8FHCmyDEAePgCGP2g== X-Google-Smtp-Source: ABdhPJwFNoMqquQx1OWVq0gCdN+Mdut2Dh9mMMcZcEKf0yTpl06AU/mt9KPvLWww8e4dCZ0odAGy3w== X-Received: by 2002:a62:3486:0:b029:24c:34c0:3c7a with SMTP id b128-20020a6234860000b029024c34c03c7amr8292456pfa.36.1618372553611; Tue, 13 Apr 2021 20:55:53 -0700 (PDT) Received: from slime ([139.198.121.254]) by smtp.gmail.com with ESMTPSA id n22sm16257109pgf.42.2021.04.13.20.55.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Apr 2021 20:55:53 -0700 (PDT) From: xiaojun.zhao141@gmail.com X-Google-Original-From: Date: Wed, 14 Apr 2021 11:55:48 +0800 To: mbenes@suse.cz Cc: josef@toxicpanda.com, linux-kernel@vger.kernel.org Subject: the qemu-nbd process automatically exit with the commit 43347d56c 'livepatch: send a fake signal to all blocking tasks' Message-ID: <20210414115548.0cdb529b@slime> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I found the qemu-nbd process(started with qemu-nbd -t -c /dev/nbd0 nbd.qcow2) will automatically exit when I patched for functions of the nbd with livepatch. The nbd relative source: static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev) { struct nbd_config *config = nbd->config; int ret; ret = nbd_start_device(nbd); if (ret) return ret; if (max_part) bdev->bd_invalidated = 1; mutex_unlock(&nbd->config_lock); ret = wait_event_interruptible(config->recv_wq, atomic_read(&config->recv_threads) == 0); if (ret) sock_shutdown(nbd); flush_workqueue(nbd->recv_workq); mutex_lock(&nbd->config_lock); nbd_bdev_reset(bdev); /* user requested, ignore socket errors */ if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags)) ret = 0; if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags)) ret = -ETIMEDOUT; return ret; } When the nbd waits for atomic_read(&config->recv_threads) == 0, the klp will send a fake signal to it then the qemu-nbd process exits. And the signal of sysfs to control this action was removed in the commit 10b3d52790e 'livepatch: Remove signal sysfs attribute'. Are there other ways to control this action? How? Thanks very much.