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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 4C353C433E2 for ; Fri, 11 Sep 2020 12:22:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9F882078D for ; Fri, 11 Sep 2020 12:22:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599826926; bh=p0dMZYlvMuBFRvmCSlPIVCxaoQeDTgEw+OKygz501WY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=jDov475U/2stVI7Q841Lx3eXeDv5y+KSWyFJUyyKQu9LOgzXZU6D+5v/e4S02/UTc lh49FP2a3UoxR9wylgNOjUV1qppNtzpravp8yzwiUleinYKGXwOCp+GvuwUsMz6TTc Or0ku3ehAYondEGVNF+Pq8rB2pBDWM0SqcK2Hc8c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725885AbgIKMWB (ORCPT ); Fri, 11 Sep 2020 08:22:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:33506 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725876AbgIKMUz (ORCPT ); Fri, 11 Sep 2020 08:20:55 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CC44821D40; Fri, 11 Sep 2020 12:20:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599826818; bh=p0dMZYlvMuBFRvmCSlPIVCxaoQeDTgEw+OKygz501WY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=j6OvDJk9lxBEbRg4B+J1hnhaSFZ0S/2rb1x8+sJ/FOilMRPj58ezUJmV6D19UauvF nkSocYDX6gFzgo3xcje+GaziUM4uhAsw9W56BGftYo/mz0h4wN8n0x9oZUTZ/60Pbx USU/zyrOBaXf379zyB0fBe/zkmRgv1cLGH3MfeeI= Date: Fri, 11 Sep 2020 14:20:24 +0200 From: Greg Kroah-Hartman To: Bob Peterson Cc: Salvatore Bonaccorso , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Andreas Gruenbacher , Sasha Levin , Daniel Craig , Nicolas Courtel Subject: Re: [PATCH 4.19 142/206] gfs2: fix use-after-free on transaction ail lists Message-ID: <20200911122024.GA3758477@kroah.com> References: <20200623195316.864547658@linuxfoundation.org> <20200623195323.968867013@linuxfoundation.org> <20200910194319.GA131386@eldamar.local> <20200911115816.GB3717176@kroah.com> <942693093.16771250.1599826115915.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <942693093.16771250.1599826115915.JavaMail.zimbra@redhat.com> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Sep 11, 2020 at 08:08:35AM -0400, Bob Peterson wrote: > ----- 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. What commit needs to be added to a stable release? confused, greg k-h