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=-15.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 0C8A3C433E0 for ; Fri, 26 Mar 2021 15:01:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD7ED61A28 for ; Fri, 26 Mar 2021 15:01:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230226AbhCZPBN (ORCPT ); Fri, 26 Mar 2021 11:01:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230187AbhCZPBC (ORCPT ); Fri, 26 Mar 2021 11:01:02 -0400 Received: from mail-io1-xd2c.google.com (mail-io1-xd2c.google.com [IPv6:2607:f8b0:4864:20::d2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F5FBC0613AA for ; Fri, 26 Mar 2021 08:01:02 -0700 (PDT) Received: by mail-io1-xd2c.google.com with SMTP id k8so5650172iop.12 for ; Fri, 26 Mar 2021 08:01:02 -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=bg/XFgK0j4Bi2nzOGM6CJPuGBSSM2wwPb1IUUNZ4ZrY=; b=w5p4jCPEbegwqL/nLPd0eJhquxW4K7gr74rDlgmo0q9j5vfRhtfBbo3QQa8S56E8fu AGx2JxN0WMKpb2iZSEFWWrZE76sPsjvq7FRce0E2ewdJa2iSVOZcPR8WzLEFnx6w+ZPU YMDPY8WM5jVGiSkwE6QdEoJlpALgByfLgkqQ+vh/vtDanm1fByUbHfAGpasJCLNoTSeH 93D7GXS8OzVYnnnPTln82sGuVUWABUnlMZ8tW6W9+qsJ2JdQ5emGr1422YvR+UXYDRdK hWRucUvSjF3XYTluWRew/75UOe0ljhp2ooDHLivMCE97IflSY5mdjTalDMt5NVqrjsv7 4h8g== 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=bg/XFgK0j4Bi2nzOGM6CJPuGBSSM2wwPb1IUUNZ4ZrY=; b=mg10Et8dKcGaXuHJVfOm+o3ev8bWc+ACJpTDQYU2XgAOwroFIZUSNMQljRZQYl0zjO pBEckruSaVNOyW67Ooa46wUMtxj8RWcnZSTqaYCQWbvgfZYubvmQNVJCiKHdg2Skl5JW F6Mm3ARozIQR1/uvoYU3OfcGSy3Q0Gvh4zsp+h0k9kXqgpyHFttWWyWvTR/klgqh5TJ1 jaxi6a8uFY3OWapxkOxvd2jwRiRInPFALa429azc3JzSw9s1PBBPZk7sHKatfLfmHYQj mg39CDwejtUVuba+qq4Cm/o10K/uzifxNN2kBks0DkdjqTZxmNkUsm7UuGdze9aQSw+Z UI4w== X-Gm-Message-State: AOAM533FwBE3TU+8vdNQ26xYmhMJLY1Tm+vHwH5wmw9V9W97r248Y8iS uFZBVErwiQvrqf9Wj2H7kFvzIA== X-Google-Smtp-Source: ABdhPJztBUwc5LhorRM9v0qt8CshTMiYbtZYm1iwC/n0UNrWtWPlWKltgXE2SKA9UpeDT9fnUgobjQ== X-Received: by 2002:a05:6602:21cd:: with SMTP id c13mr10293909ioc.44.1616770861565; Fri, 26 Mar 2021 08:01:01 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id i67sm4584479ioa.3.2021.03.26.08.01.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 26 Mar 2021 08:01:01 -0700 (PDT) Subject: Re: [PATCH 2/8] kernel: unmask SIGSTOP for IO threads To: Oleg Nesterov Cc: io-uring@vger.kernel.org, torvalds@linux-foundation.org, ebiederm@xmission.com, metze@samba.org, linux-kernel@vger.kernel.org References: <20210326003928.978750-1-axboe@kernel.dk> <20210326003928.978750-3-axboe@kernel.dk> <20210326134840.GA1290@redhat.com> From: Jens Axboe Message-ID: Date: Fri, 26 Mar 2021 09:01:00 -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: <20210326134840.GA1290@redhat.com> 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 7:48 AM, Oleg Nesterov wrote: > Jens, sorry, I got lost :/ Let's bring you back in :-) > On 03/25, Jens Axboe wrote: >> >> With IO threads accepting signals, including SIGSTOP, > > where can I find this change? Looks like I wasn't cc'ed... It's this very series. >> unmask the >> SIGSTOP signal from the default blocked mask. >> >> Signed-off-by: Jens Axboe >> --- >> kernel/fork.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/kernel/fork.c b/kernel/fork.c >> index d3171e8e88e5..d5a40552910f 100644 >> --- a/kernel/fork.c >> +++ b/kernel/fork.c >> @@ -2435,7 +2435,7 @@ struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node) >> tsk = copy_process(NULL, 0, node, &args); >> if (!IS_ERR(tsk)) { >> sigfillset(&tsk->blocked); >> - sigdelsetmask(&tsk->blocked, sigmask(SIGKILL)); >> + sigdelsetmask(&tsk->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP)); > > siginitsetinv(blocked, sigmask(SIGKILL)|sigmask(SIGSTOP)) but this is minor. Ah thanks. > To remind, either way this is racy and can't really help. > > And if "IO threads accepting signals" then I don't understand why. Sorry, > I must have missed something. I do think the above is a no-op at this point, and we can probably just kill it. Let me double check, hopefully we can just remove this blocked part. -- Jens Axboe