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=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 91E31C433C1 for ; Fri, 26 Mar 2021 14:50:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58A7B61A10 for ; Fri, 26 Mar 2021 14:50:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230135AbhCZOuT (ORCPT ); Fri, 26 Mar 2021 10:50:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230114AbhCZOuG (ORCPT ); Fri, 26 Mar 2021 10:50:06 -0400 Received: from mail-io1-xd36.google.com (mail-io1-xd36.google.com [IPv6:2607:f8b0:4864:20::d36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25252C0613AA for ; Fri, 26 Mar 2021 07:50:06 -0700 (PDT) Received: by mail-io1-xd36.google.com with SMTP id r193so5627603ior.9 for ; Fri, 26 Mar 2021 07:50:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=NCrS9iSkYyQTH7Kgs8zwkcq/baRWu0lLKcFuH4cqgFg=; b=iGK/gRZfeC3cbbqAjOASxYWKK53wUvLo9OenDtjIhCKQlvUE1avGlEYpUsj6gV4ydp JQeU50n/4XtXc+5HtNCg139qbO58VXQjcBPvcgQLH9fCnxO/feZnCurbksMS2hEM+vdU fMwzgs2BCfQVKDCPqppp6c9hGyuwMwoP4wstuVVZ+UEO2gIjG5JQgIFcTbOy5E7y6vAW +xtKKVseu+9UBTxumxF8gKiXJzdqHh7lzn4Fe7UfPaTwHXaD+FkVM+yf8vsevGDoofAU jkuQV96v/kw2VzDMBNAJJdJwiSJDQ0kTJkMhxyvvzHllwFhv95N/MZE6NZRTXpiD6dqV NCxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=NCrS9iSkYyQTH7Kgs8zwkcq/baRWu0lLKcFuH4cqgFg=; b=D0q0umj+qpxriV+t9tuiOiyCiJdR5er7jqHo6zzctQ9FMSTYeVmY8bVK3IFRFayABy NGtXhjH9ycsgFFGV3NdryJVoPx6lw4FkxjSrcsH8YwPZlbvrou+Fo2wXv34I8z15AMYN fmOQo3ffHrlzIzo+bZ7VrNXwI2KHsPFc53FC/49LTYnJ2MtiLiUe6WcU1nhdplwJy9Sq 2YTiteF0tsEUk+jfYNmsJoqAZtbBDetPQhT3AdxVoznwvl2H5s64h8/OfNwm5ppNFTVv A7HRaWMQOTkPoC0TLabGWy9IFUIlNxCcBXqfYvC5yWC8wp11Eax+QInFPbEGb4oN03M9 IGBQ== X-Gm-Message-State: AOAM531V132Eo0gxTmVmY4UuWVVjsmQbPynvAv4RieeztmewXmXKBhga OMi+QFJPo6r274Vecx13katyUQ== X-Google-Smtp-Source: ABdhPJxQJtEQI5UCABz+W+UvbPcm+d2yBOgPoJQMIVxMaqQBXBW4iwT+7Y5WPc1z92XE8UEbGdOMAA== X-Received: by 2002:a02:7f8c:: with SMTP id r134mr12274121jac.95.1616770205481; Fri, 26 Mar 2021 07:50:05 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id t9sm4339079ioi.27.2021.03.26.07.50.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 26 Mar 2021 07:50:04 -0700 (PDT) Subject: Re: [PATCH 0/6] Allow signals for IO threads To: Stefan Metzmacher , io-uring@vger.kernel.org Cc: torvalds@linux-foundation.org, ebiederm@xmission.com, oleg@redhat.com, linux-kernel@vger.kernel.org References: <20210326003928.978750-1-axboe@kernel.dk> <8efd9977-003b-be65-8ae2-4b04d8dd1224@samba.org> <0c91d9e7-82cd-bec2-19ae-cc592ec757c6@kernel.dk> <66fa3cfc-4161-76fe-272e-160097f32a53@kernel.dk> <67a83ad5-1a94-39e5-34c7-6b2192eb7edb@samba.org> From: Jens Axboe Message-ID: Date: Fri, 26 Mar 2021 08:50:03 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <67a83ad5-1a94-39e5-34c7-6b2192eb7edb@samba.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/26/21 8:43 AM, Stefan Metzmacher wrote: > Am 26.03.21 um 15:38 schrieb Jens Axboe: >> On 3/26/21 7:59 AM, Jens Axboe wrote: >>> On 3/26/21 7:54 AM, Jens Axboe wrote: >>>>> The KILL after STOP deadlock still exists. >>>> >>>> In which tree? Sounds like you're still on the old one with that >>>> incremental you sent, which wasn't complete. >>>> >>>>> Does io_wq_manager() exits without cleaning up on SIGKILL? >>>> >>>> No, it should kill up in all cases. I'll try your stop + kill, I just >>>> tested both of them separately and didn't observe anything. I also ran >>>> your io_uring-cp example (and found a bug in the example, fixed and >>>> pushed), fwiw. >>> >>> I can reproduce this one! I'll take a closer look. >> >> OK, that one is actually pretty straight forward - we rely on cleaning >> up on exit, but for fatal cases, get_signal() will call do_exit() for us >> and never return. So we might need a special case in there to deal with >> that, or some other way of ensuring that fatal signal gets processed >> correctly for IO threads. > > And if (fatal_signal_pending(current)) doesn't prevent get_signal() > from being called? Usually yes, but this case is first doing SIGSTOP, so we're waiting in get_signal() -> do_signal_stop() when the SIGKILL arrives. Hence there's no way to catch it in the worker themselves. -- Jens Axboe