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[23.128.96.18]) by mx.google.com with ESMTP id u23si1724115edq.185.2020.09.11.10.38.04; Fri, 11 Sep 2020 10:38:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=N08nDPjJ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726488AbgIKRhd (ORCPT + 99 others); Fri, 11 Sep 2020 13:37:33 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:50215 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725964AbgIKMtT (ORCPT ); Fri, 11 Sep 2020 08:49:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599828558; 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=vDIsWH1xqD67Gmco0QgZOe8QgfyuuJPWftyBiVMV+go=; b=N08nDPjJxGEfsk+7sXw1Ofmyhr6ozjnyxz3RN7HPXCZmI94JxseDKfL+8nk6jFofabQK5k aGDTu2dPnYP6yJViLOJgrjd0fPr0RSw13MVAZ4AjAz3LRbtxLSq6jxl3Q0gDRRmubLaMZP 65F5W+Jfb8udqMUgkmhDyHCZ4i0RkjM= 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-334-4nAHGMVdN5OuEFwH4P4QhA-1; Fri, 11 Sep 2020 08:49:16 -0400 X-MC-Unique: 4nAHGMVdN5OuEFwH4P4QhA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E966681F000; Fri, 11 Sep 2020 12:49:14 +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 D7EAB5C1BD; Fri, 11 Sep 2020 12:49:14 +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 C770B180B655; Fri, 11 Sep 2020 12:49:14 +0000 (UTC) Date: Fri, 11 Sep 2020 08:49:14 -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: <1542145456.16781948.1599828554609.JavaMail.zimbra@redhat.com> In-Reply-To: <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> <20200911122024.GA3758477@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, 10.4.195.27] Thread-Topic: gfs2: fix use-after-free on transaction ail lists Thread-Index: DCiqUq9HQ4QOwAvvCyrviVZWuBtO2w== X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > 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 Sorry Greg, It's pretty early here and the caffeine hadn't quite hit my system. The problem is most likely that 4.19.132 is missing this upstream patch: cbcc89b630447ec7836aa2b9242d9bb1725f5a61 I'm not sure how or why 83d060ca8d90fa1e3feac227f995c013100862d3 got put into stable without a stable CC but cbcc89b6304 is definitely required. I'd like to suggest Salvatore try cherry-picking this patch to see if it fixes the problem, and if so, perhaps Greg can add it to stable. Regards, Bob Peterson GFS2 File Systems