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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 D9CF1C433C1 for ; Fri, 26 Mar 2021 15:24:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA06861A27 for ; Fri, 26 Mar 2021 15:24:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230243AbhCZPXy (ORCPT ); Fri, 26 Mar 2021 11:23:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230236AbhCZPXl (ORCPT ); Fri, 26 Mar 2021 11:23:41 -0400 Received: from hr2.samba.org (hr2.samba.org [IPv6:2a01:4f8:192:486::2:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7827C0613AA; Fri, 26 Mar 2021 08:23:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=samba.org; s=42; h=Date:Message-ID:From:Cc:To; bh=g2ov54Wvo719yXCzrq89z7p3cmF5FT7ALxcJeE1hBUY=; b=jpEeDMsPWOwCg4VMrXNgjU7A+I B2cqHaZxWCmb4BVbKEW2NC60WH8DoH3fWQ6/HBxhNNr+v8m4en3kxjaaDw+Phqk6dWjdCubNnAUdc 97bD4zPs9wOiyiv1dFscVZ/tGUHj4icowgl0NXSOWEx3heIAtWQn3iVYCd9OrXufJyCqOV6+MfDh2 7SjyG9vItBPfFR3MekyT16iznp+CechmpcCNHNHISd7sgK64u2Tc7dkYamoILEJaFoC4gLS5VlO/N jCgfS1PcEJr5YoiFRXeU+J0C3Uxqm3K0TZ6S4hlHeG3BYwQ8rVZ3auJa30vq4gNwVGYGv4A0V6vtb 1eUKo25DDqxCrF0PL8c0Bx2ML//bneHPHSmg4+KFgNJ5upZpr280tU+3ADPYW70oedh9EZRKpHbGp k0ToLT1HxPhXRwWpuhNt5Zq9VXb5fhLizPvUx6ty1yzTf7hUR16PqYKgb9gmjUoxr3rq4fHkOpYSH eXrPmAUBR9tSaAKYIJ0wuI+B; Received: from [127.0.0.2] (localhost [127.0.0.1]) by hr2.samba.org with esmtpsa (TLS1.3:ECDHE_RSA_CHACHA20_POLY1305:256) (Exim) id 1lPoJF-0003W2-Ge; Fri, 26 Mar 2021 15:23:37 +0000 To: Jens Axboe , Oleg Nesterov Cc: io-uring@vger.kernel.org, torvalds@linux-foundation.org, ebiederm@xmission.com, linux-kernel@vger.kernel.org References: <20210326003928.978750-1-axboe@kernel.dk> <20210326003928.978750-3-axboe@kernel.dk> <20210326134840.GA1290@redhat.com> From: Stefan Metzmacher Subject: Re: [PATCH 2/8] kernel: unmask SIGSTOP for IO threads Message-ID: <8f2a4b48-77c9-393f-5194-100ed63c05fc@samba.org> Date: Fri, 26 Mar 2021 16:23:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 26.03.21 um 16:01 schrieb Jens Axboe: > 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. Is this really correct to drop in your "kernel: stop masking signals in create_io_thread()" commit? I don't assume signals wanted by userspace should potentially handled in an io_thread... e.g. things set with fcntl(fd, F_SETSIG,) used together with F_SETLEASE? metze