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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 9ECF7C433C1 for ; Fri, 26 Mar 2021 20:32:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8769F61A18 for ; Fri, 26 Mar 2021 20:32:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230043AbhCZUas (ORCPT ); Fri, 26 Mar 2021 16:30:48 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:57498 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229957AbhCZUar (ORCPT ); Fri, 26 Mar 2021 16:30:47 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lPt6M-00A4fH-HK; Fri, 26 Mar 2021 14:30:39 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=fess.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lPt6J-00B7ep-ME; Fri, 26 Mar 2021 14:30:38 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Jens Axboe Cc: io-uring@vger.kernel.org, torvalds@linux-foundation.org, metze@samba.org, oleg@redhat.com, linux-kernel@vger.kernel.org References: <20210326155128.1057078-1-axboe@kernel.dk> <20210326155128.1057078-3-axboe@kernel.dk> Date: Fri, 26 Mar 2021 15:29:36 -0500 In-Reply-To: <20210326155128.1057078-3-axboe@kernel.dk> (Jens Axboe's message of "Fri, 26 Mar 2021 09:51:15 -0600") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1lPt6J-00B7ep-ME;;;mid=;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19vqmGiyer57AEM9hR7ONnpmC199gaFPKM= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH 2/7] io_uring: handle signals for IO threads like a normal thread X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Jens Axboe writes: > We go through various hoops to disallow signals for the IO threads, but > there's really no reason why we cannot just allow them. The IO threads > never return to userspace like a normal thread, and hence don't go through > normal signal processing. Instead, just check for a pending signal as part > of the work loop, and call get_signal() to handle it for us if anything > is pending. > > With that, we can support receiving signals, including special ones like > SIGSTOP. > > Signed-off-by: Jens Axboe > --- > fs/io-wq.c | 24 +++++++++++++++++------- > fs/io_uring.c | 12 ++++++++---- > 2 files changed, 25 insertions(+), 11 deletions(-) > > diff --git a/fs/io-wq.c b/fs/io-wq.c > index b7c1fa932cb3..3e2f059a1737 100644 > --- a/fs/io-wq.c > +++ b/fs/io-wq.c > @@ -16,7 +16,6 @@ > #include > #include > #include > -#include > > #include "../kernel/sched/sched.h" > #include "io-wq.h" > @@ -503,10 +502,16 @@ static int io_wqe_worker(void *data) > if (io_flush_signals()) > continue; > ret = schedule_timeout(WORKER_IDLE_TIMEOUT); > - if (try_to_freeze() || ret) > + if (signal_pending(current)) { > + struct ksignal ksig; > + > + if (fatal_signal_pending(current)) > + break; > + if (get_signal(&ksig)) > + continue; ^^^^^^^^^^^^^^^^^^^^^^ That is wrong. You are promising to deliver a signal to signal handler and them simply discarding it. Perhaps: if (!get_signal(&ksig)) continue; WARN_ON(!sig_kernel_stop(ksig->sig)); break; Eric