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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 158A1C43381 for ; Wed, 20 Mar 2019 13:29:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7A55213F2 for ; Wed, 20 Mar 2019 13:29:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553088584; bh=r5CcAPwZR0UU8uWco8mxXvnypDrWuxeTVLrwSeqAlR0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=rMm9t2XDEdPESVdq/T0iHBWsabUSJkVOHDpaTnvnIvK2cLqEens6XBuWqdmW8d1yT slPNuQPifeXiYwv65IEIyv2BA0y31Uc8byOa81ghA4qkpG7QEcS6Gy2Sr+TVjLmckL j+ulfQNWGTO58GAim/cvKyWCp1soYzh88B81Ouc4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727873AbfCTN3k (ORCPT ); Wed, 20 Mar 2019 09:29:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:52056 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726644AbfCTN3i (ORCPT ); Wed, 20 Mar 2019 09:29:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 75CD9AF1F; Wed, 20 Mar 2019 13:29:37 +0000 (UTC) Date: Wed, 20 Mar 2019 14:29:36 +0100 From: Michal Hocko To: Oleg Nesterov Cc: syzbot , chanho.min@lge.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, pavel@ucw.cz, rafael.j.wysocki@intel.com, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Subject: Re: WARNING: syz-executor still has locks held! Message-ID: <20190320132936.GB8696@dhcp22.suse.cz> References: <0000000000000e4a41057b6c9792@google.com> <0000000000004cdec6058485b2ce@google.com> <20190320131655.GA8696@dhcp22.suse.cz> <20190320132410.GB21673@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190320132410.GB21673@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed 20-03-19 14:24:11, Oleg Nesterov wrote: > On 03/20, Michal Hocko wrote: > > > > Yes we do hold the cgred mutex while calling freezable_schedule but why > > are we getting a warning is not really clear to me. The task should be > > hidden from the freezer so why do we warn at all? > > try_to_freeze() calls debug_check_no_locks_held() and this makes sense. Yes it does. But it already ignores PF_NOFREEZE tasks and I fail to see why is PF_FREEZER_SKIP any different. Yes we know we are holding the lock and we have discussed that left and right before the patch was merged but it seems that skipping the task was the only viable option to fix suspend issues as removing the cgred is way way too complicated. That being said, I was arguing against the patch initially because it was a hack but sometimes that is the only way viable path short term. -- Michal Hocko SUSE Labs