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=-6.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 2BE9AC43461 for ; Fri, 11 Sep 2020 12:10:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA9F8206F4 for ; Fri, 11 Sep 2020 12:10:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ju/gItcH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725872AbgIKMKX (ORCPT ); Fri, 11 Sep 2020 08:10:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:23561 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725850AbgIKMIo (ORCPT ); Fri, 11 Sep 2020 08:08:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599826119; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xVg8NZb3XREmzVribQHfAuVjodAq3CHk37cp1IALDMM=; b=Ju/gItcHTw51TT2+CxXIhgnLBUtBg6kK44LKS2UpsCsY39saK8659+sNPFIMxrppuB9zGH Wf9umbMMmOIjcHRl47nIaKsGfJaj7mPiQp3YdBF+I4fL4/szYYCLLd9RpAq99rZOx1DzjG /h/KXJ3GXMIv/l2Gp2PEk1SgDJoJEjI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-232-UxymmEKUNsKZHYa3d4mO6A-1; Fri, 11 Sep 2020 08:08:38 -0400 X-MC-Unique: UxymmEKUNsKZHYa3d4mO6A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CE6E910082F9; Fri, 11 Sep 2020 12:08:36 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9B52B7E8F1; Fri, 11 Sep 2020 12:08:36 +0000 (UTC) Received: from zmail21.collab.prod.int.phx2.redhat.com (zmail21.collab.prod.int.phx2.redhat.com [10.5.83.24]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 08193181A050; Fri, 11 Sep 2020 12:08:36 +0000 (UTC) Date: Fri, 11 Sep 2020 08:08:35 -0400 (EDT) From: Bob Peterson To: Greg Kroah-Hartman Cc: Salvatore Bonaccorso , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Andreas Gruenbacher , Sasha Levin , Daniel Craig , Nicolas Courtel Message-ID: <942693093.16771250.1599826115915.JavaMail.zimbra@redhat.com> In-Reply-To: <20200911115816.GB3717176@kroah.com> References: <20200623195316.864547658@linuxfoundation.org> <20200623195323.968867013@linuxfoundation.org> <20200910194319.GA131386@eldamar.local> <20200911115816.GB3717176@kroah.com> Subject: Re: [PATCH 4.19 142/206] gfs2: fix use-after-free on transaction ail lists MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.3.112.23, 10.4.195.2] Thread-Topic: gfs2: fix use-after-free on transaction ail lists Thread-Index: 7tAZ6eQVWu/XBrrfQ/Ia5mWO+IMFDw== X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > On Thu, Sep 10, 2020 at 09:43:19PM +0200, Salvatore Bonaccorso wrote: > > Hi, > > > > On Tue, Jun 23, 2020 at 09:57:50PM +0200, Greg Kroah-Hartman wrote: > > > From: Bob Peterson > > > > > > [ Upstream commit 83d060ca8d90fa1e3feac227f995c013100862d3 ] > > > > > > Before this patch, transactions could be merged into the system > > > transaction by function gfs2_merge_trans(), but the transaction ail > > > lists were never merged. Because the ail flushing mechanism can run > > > separately, bd elements can be attached to the transaction's buffer > > > list during the transaction (trans_add_meta, etc) but quickly moved > > > to its ail lists. Later, in function gfs2_trans_end, the transaction > > > can be freed (by gfs2_trans_end) while it still has bd elements > > > queued to its ail lists, which can cause it to either lose track of > > > the bd elements altogether (memory leak) or worse, reference the bd > > > elements after the parent transaction has been freed. > > > > > > Although I've not seen any serious consequences, the problem becomes > > > apparent with the previous patch's addition of: > > > > > > gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list)); > > > > > > to function gfs2_trans_free(). > > > > > > This patch adds logic into gfs2_merge_trans() to move the merged > > > transaction's ail lists to the sdp transaction. This prevents the > > > use-after-free. To do this properly, we need to hold the ail lock, > > > so we pass sdp into the function instead of the transaction itself. > > > > > > Signed-off-by: Bob Peterson > > > Signed-off-by: Andreas Gruenbacher > > > Signed-off-by: Sasha Levin (snip) > > > > In Debian two user confirmed issues on writing on a GFS2 partition > > with this commit applied. The initial Debian report is at > > https://bugs.debian.org/968567 and Daniel Craig reported it into > > Bugzilla at https://bugzilla.kernel.org/show_bug.cgi?id=209217 . > > > > Writing to a gfs2 filesystem fails and results in a soft lookup of the > > machine for kernels with that commit applied. I cannot reporduce the > > issue myself due not having a respective setup available, but Daniel > > described a minimal serieos of steps to reproduce the issue. > > > > This might affect as well other stable series where this commit was > > applied, as there was a similar report for someone running 5.4.58 in > > https://www.redhat.com/archives/linux-cluster/2020-August/msg00000.html > > Can you report this to the gfs2 developers? > > thanks, > > greg k-h Hi Greg, No need. The patch came from the gfs2 developers. I think he just wants it added to a stable release. Regards, Bob Peterson GFS2 File System