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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 28AC7C433B4 for ; Fri, 21 May 2021 07:54:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E64B600CC for ; Fri, 21 May 2021 07:54:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231605AbhEUHz5 (ORCPT ); Fri, 21 May 2021 03:55:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231301AbhEUHzz (ORCPT ); Fri, 21 May 2021 03:55:55 -0400 Received: from mail-vs1-xe36.google.com (mail-vs1-xe36.google.com [IPv6:2607:f8b0:4864:20::e36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8ABE3C061574 for ; Fri, 21 May 2021 00:54:31 -0700 (PDT) Received: by mail-vs1-xe36.google.com with SMTP id q6so5698609vsp.13 for ; Fri, 21 May 2021 00:54:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yA7Lkm/nXDMCfmn4EBtAJW5GRrIK88MdQhqjgo97iYc=; b=C18mRKWikKVx1cic8io2JbRa79yx/52/8m0xFuj1FZsu7EuOsgMlp9RDIqjkJ+sDKC 1POBz/VL0Z4NxyJd14bYcBLpZn4v8THFtAPLJ+E2T4udz4+QjiUwEUyd9zjffvf160LC cDP3k4gS2MBFFOQBoNEmuTWqlLYwdQrXg1XDE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yA7Lkm/nXDMCfmn4EBtAJW5GRrIK88MdQhqjgo97iYc=; b=PI+OZhj0aqc3cZyiImd83DaLxV50hhZtIUtgZf0D9TsdLBldvOJ9AQ/HExMhZTmtq1 7TdrDzZ4BgonyiQ/2rZhSUdXRfeTkM5hxTShHRozFW2sgOueTs1jo1f33q7O+gzlnhue tH5j6g/87eMY86mprTzUPmMrPUrUuSZRVM+bxhr2Cz0Ump1YQeNL3w00wPNyUR1BVPtx H141Wh1cDhEGPD5Sf2UO/LyjHTCQZ5QPVC8crBSgbkUhOwcRSy8fVeIscViBjl2KFjUj BYjVF76KClvc5K45tgNCzNZwQ7YHWCi/3riEzVc4LCLDtMbmg+fJ6IqVOAHe0/19FioJ 4WEg== X-Gm-Message-State: AOAM533LyM7KNBDSQNxUqeU5G1CjaHhbt+f/BFPmBHltvnDVsb+fGoQO uV5p8wNbULWXMTesd8bgV0af2bo4XRmAskobHpNBig== X-Google-Smtp-Source: ABdhPJwHx/FKMoZFaVW7VqWkqliu9Li95xQWM99p2HAvSRFx8ZjGMbpLHEgoCCMXb32SC/WfuuuWfF1ROQUYrmO6eGc= X-Received: by 2002:a05:6102:b06:: with SMTP id b6mr8147911vst.21.1621583670705; Fri, 21 May 2021 00:54:30 -0700 (PDT) MIME-Version: 1.0 References: <20210520154654.1791183-1-groug@kaod.org> <20210520154654.1791183-2-groug@kaod.org> In-Reply-To: From: Miklos Szeredi Date: Fri, 21 May 2021 09:54:19 +0200 Message-ID: Subject: Re: [PATCH v4 1/5] fuse: Fix leak in fuse_dentry_automount() error path To: Al Viro Cc: Greg Kurz , virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, virtio-fs-list , Stefan Hajnoczi , Max Reitz , Vivek Goyal Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 May 2021 at 21:45, Al Viro wrote: > > On Thu, May 20, 2021 at 05:46:50PM +0200, Greg Kurz wrote: > > Some rollback was forgotten during the addition of crossmounts. > > Have you actually tested that? Because I strongly suspect that > by that point the ownership of fc and fm is with sb and those > should be taken care of by deactivate_locked_super(). Not quite. Patch looks correct because destruction of fm is done in fuse_put_super(), which only gets called if the sb initialization gets as far as setting up sb->s_root, which only happens after the successful fuse_fill_super_submount() call in this case. Doing the destruction from the various ->kill_sb() instances instead of from ->put_super() would also fix this, but I'm not quite sure that that would be any cleaner. Thanks, Miklos From mboxrd@z Thu Jan 1 00:00:00 1970 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yA7Lkm/nXDMCfmn4EBtAJW5GRrIK88MdQhqjgo97iYc=; b=C18mRKWikKVx1cic8io2JbRa79yx/52/8m0xFuj1FZsu7EuOsgMlp9RDIqjkJ+sDKC 1POBz/VL0Z4NxyJd14bYcBLpZn4v8THFtAPLJ+E2T4udz4+QjiUwEUyd9zjffvf160LC cDP3k4gS2MBFFOQBoNEmuTWqlLYwdQrXg1XDE= MIME-Version: 1.0 References: <20210520154654.1791183-1-groug@kaod.org> <20210520154654.1791183-2-groug@kaod.org> In-Reply-To: From: Miklos Szeredi Date: Fri, 21 May 2021 09:54:19 +0200 Message-ID: Content-Type: text/plain; charset="UTF-8" Subject: Re: [Virtio-fs] [PATCH v4 1/5] fuse: Fix leak in fuse_dentry_automount() error path List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Al Viro Cc: linux-kernel@vger.kernel.org, virtio-fs-list , Max Reitz , linux-fsdevel@vger.kernel.org, virtualization@lists.linux-foundation.org, Vivek Goyal On Thu, 20 May 2021 at 21:45, Al Viro wrote: > > On Thu, May 20, 2021 at 05:46:50PM +0200, Greg Kurz wrote: > > Some rollback was forgotten during the addition of crossmounts. > > Have you actually tested that? Because I strongly suspect that > by that point the ownership of fc and fm is with sb and those > should be taken care of by deactivate_locked_super(). Not quite. Patch looks correct because destruction of fm is done in fuse_put_super(), which only gets called if the sb initialization gets as far as setting up sb->s_root, which only happens after the successful fuse_fill_super_submount() call in this case. Doing the destruction from the various ->kill_sb() instances instead of from ->put_super() would also fix this, but I'm not quite sure that that would be any cleaner. Thanks, Miklos