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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D985C00A5A for ; Thu, 19 Jan 2023 07:05:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229593AbjASHFh (ORCPT ); Thu, 19 Jan 2023 02:05:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbjASHFf (ORCPT ); Thu, 19 Jan 2023 02:05:35 -0500 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A192830D3 for ; Wed, 18 Jan 2023 23:05:33 -0800 (PST) Received: by mail-pj1-x102f.google.com with SMTP id b10so1507615pjo.1 for ; Wed, 18 Jan 2023 23:05:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=txG1XI7DK5qkyfzJsKyT2pWmLht7EdUGbR24ELqCUHo=; b=lxqHsMH2HIghXj4gFBlPCciC9Iw+prjvBTBsMieEaNPRpj0rthzQo0CNTH3sx6kocj AyEj86BLZB5WET6qEiF5+HPDKjPetcbMIwu44wa4YD1FHl+0X/ew3/IC5zSuHxHpK0l+ kPpPB7XJxISSXJZwCfkhzDDDEY8TN0Y/fefk466VY1C/WZQf3yRP638cfmdteBeYMyhn F8BP5t2vMlXKJvaBgZL2vRZDAj4uyXzFwjV28yciqxDchSzciyawcRkXRsTmY9oWOe9i SgWrD7lRAveYJ4ENRgIRt9S4mhdkd72ce0UoY5A0VqInxZdUqfFO2CSXMtHHFE/HerdG 9NgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=txG1XI7DK5qkyfzJsKyT2pWmLht7EdUGbR24ELqCUHo=; b=UDqu1Gqs0p2Fx5ynMoBegvwBgmy0xNfqui5RXg34gvMiygVd8PJahb9u7sav0JXFac PK9e16Kmi/X2D2NswacCbojEgBlMI60b8pI2TyM1mfmXxMoxxytJF1TUxxPsdpDZ5ZkU rRC1os2e71f6tEu3WnikfUJxeii7pYX2+7K64P0R2oIqHEQ3cVpi4PcS8Tb8MnyaqFBS tCYaxRCylLvMDLneRmi01vDDP6xK46z5YFD9bEc8lSEXSypoYxvD096nXggKDVmEhtt4 s8nclTXUMwlC38to0cBoiDBSJAbrxpOVOQY+I1565qyTo6Fy/MW4m1Tz9kdBlr2rFy12 NMrw== X-Gm-Message-State: AFqh2kqTrI8mIbw4gCUO+0PtvtDa6J5p4DuVYbrK1KxfgxCpvXmrM0lm dkyc4gbroogZwbpuNeJvoM0= X-Google-Smtp-Source: AMrXdXt58siXWKsK0SGOpumac1dFmRQ4jmOmPF5wpgCiZeEMvDmOFznZXC79asasvoPNM1i9j8atJQ== X-Received: by 2002:a17:902:7fc9:b0:194:84f2:c1ec with SMTP id t9-20020a1709027fc900b0019484f2c1ecmr10354245plb.21.1674111933032; Wed, 18 Jan 2023 23:05:33 -0800 (PST) Received: from ubuntu ([210.99.119.24]) by smtp.gmail.com with ESMTPSA id j6-20020a170902690600b00192aecb231asm24263298plk.121.2023.01.18.23.05.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Jan 2023 23:05:32 -0800 (PST) Date: Wed, 18 Jan 2023 23:05:28 -0800 From: "YoungJun.Park" To: Miklos Szeredi Cc: Alex Murray , linux-fsdevel@vger.kernel.org Subject: Re: Re: question about fuse livelock situation Message-ID: <20230119070528.GA1337007@ubuntu> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Aug 31, 2022 at 11:58:50AM +0200, Miklos Szeredi wrote: > On Tue, 30 Aug 2022 at 03:58, 박영준 wrote: > > > > I found fuse livelock situation and report it for possibility of problem. > > > > [Environment] > > 22.04 5.15.0-43-generic ubuntu kernel. > > ntfs-3g version ntfs-3g 2021.8.22 integrated FUSE 28 - Third > > Generation NTFS Driver > > > > [Problem] > > I bumped on livelock and analyze it. and concluded that it is needed > > to be fixed. > > it happends when 3 operation concurrently progressing. > > > > 1) usb detach by user. and kernel detect it. > > 2) mount.ntfs umount request & device release operation > > 3) pool-udisksd umount operation. > > > > [Conclusion] > > 1. mounted target device file must be released after /dev/fuse > > release. it makes deadlocky scenario. > > Shouldn't this be reported to ntfs-3g developers then? > > Thanks, > Miklos I reported it ntfs-3g and ubuntu bug report channel. ntfs-3g does not respond and ubuntu bug report channel response it like below. (If you want a detail scenario flow picture, calltack etc check the link https://github.com/tuxera/ntfs-3g/issues/56) > Hi > Thanks for reporting this issue - in general it is better to report bugs > via launchpad than email (e.g. by running the following command (without > the quotation marks) in a terminal: "ubuntu-bug ntfs-3g" or by > https://bugs.launchpad.net/ubuntu/+source/ntfs-3g/+filebug) > I notice you also appear to have reported this to the upstream nfts-3g > project at https://github.com/tuxera/ntfs-3g/issues/56 but have had no > response. > However, my initial thoughts when looking at this is that it appears you > can trigger a livelock within the kernel from an unprivileged user in > userspace - as such I wonder if this is a bug in the FUSE subsystem > within the Linux kernel and hence whether it should be reported to the > upstream kernel developers as well? As per > https://www.kernel.org/doc/html/v4.15/admin-guide/reporting-bugs.html it > would appear that this should be reported to the following email > addresses (assuming this is a real kernel bug rather than a bug within > the ntfs-3g userspace project): > $ ./scripts/get_maintainer.pl fs/fuse/fuse_i.h > Miklos Szeredi (maintainer:FUSE: FILESYSTEM IN USERSPACE) > linux-fsdevel@vger.kernel.org (open list:FUSE: FILESYSTEM IN USERSPACE) > linux-kernel@vger.kernel.org (open list) > Thanks, > Alex Could you explan why it shoulde be fixed in userspace? then I try to fix this issue and to report it one more based on your comment. Thanks, YoungJun park.