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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 314AFC43441 for ; Mon, 12 Nov 2018 09:51:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F3FF2223C8 for ; Mon, 12 Nov 2018 09:51:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3FF2223C8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ucw.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728134AbeKLTnu (ORCPT ); Mon, 12 Nov 2018 14:43:50 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:41921 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726597AbeKLTnu (ORCPT ); Mon, 12 Nov 2018 14:43:50 -0500 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 9550F806E7; Mon, 12 Nov 2018 10:51:19 +0100 (CET) Date: Mon, 12 Nov 2018 10:51:21 +0100 From: Pavel Machek To: Chanho Min Cc: "Rafael J. Wysocki" , Len Brown , Andrew Morton , "Eric W. Biederman" , Christian Brauner , Oleg Nesterov , Anna-Maria Gleixner , Alexander Viro , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Seungho Park , Inkyu Hwang , Donghwan Jung , Jongsung Kim Subject: Re: [PATCH v2] exec: make de_thread() freezable Message-ID: <20181112095121.GA5695@amd> References: <1541994885-20059-1-git-send-email-chanho.min@lge.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vtzGhvizbBRQ85DL" Content-Disposition: inline In-Reply-To: <1541994885-20059-1-git-send-email-chanho.min@lge.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --vtzGhvizbBRQ85DL Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon 2018-11-12 12:54:45, Chanho Min wrote: > Suspend fails due to the exec family of functions blocking the freezer. > The casue is that de_thread() sleeps in TASK_UNINTERRUPTIBLE waiting for > all sub-threads to die, and we have the deadlock if one of them is frozen. > This also can occur with the schedule() waiting for the group thread lead= er > to exit if it is frozen. >=20 > In our machine, it causes freeze timeout as bellows. >=20 > Freezing of tasks failed after 20.010 seconds (1 tasks refusing to freeze= , wq_busy=3D0): > setcpushares-ls D ffffffc00008ed70 0 5817 1483 0x0040000d > Call trace: > [] __switch_to+0x88/0xa0 > [] __schedule+0x1bc/0x720 > [] schedule+0x40/0xa8 > [] flush_old_exec+0xdc/0x640 > [] load_elf_binary+0x2a8/0x1090 > [] search_binary_handler+0x9c/0x240 > [] load_script+0x20c/0x228 > [] search_binary_handler+0x9c/0x240 > [] do_execveat_common.isra.14+0x4f8/0x6e8 > [] compat_SyS_execve+0x38/0x48 > [] el0_svc_naked+0x24/0x28 >=20 > To fix this, make de_thread() freezable. It looks safe and works fine. >=20 > Changes in v2: > - changes for the same reason in "if (!thread_group_leader(tsk))" branch. > (reported by Oleg) >=20 > Suggested-by: Oleg Nesterov > Signed-off-by: Chanho Min Acked-by: Pavel Machek --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --vtzGhvizbBRQ85DL Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlvpTRkACgkQMOfwapXb+vLcLwCeOd2jytn3uSdvAQWh2K8+RkKK UYkAnREFbYw3qGUcs0CX79xse5VLdBGU =L4si -----END PGP SIGNATURE----- --vtzGhvizbBRQ85DL--