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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 5E7E9C433DF for ; Tue, 23 Jun 2020 20:15:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A6E421527 for ; Tue, 23 Jun 2020 20:15:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592943319; bh=OXoq7U7vrOFSjjoT5wdL3Gv4N5mXgeMwFrsSNSlyM4M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JwdjM/LH/rggmhiYJ/tkzY9yqo5jpcRBy1eKb4fhlXiifcQcCs+ZSi9MtNfdeANNK 3cXLaFFAW5KV710Renb0G7pAcepeF2G448ycx52JICgwHUxBr8VWtePM4SyNjCwSYz YDa1bIX6QverTYzGl9sh2v5yYdp296JXHQdNK18s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389273AbgFWUPR (ORCPT ); Tue, 23 Jun 2020 16:15:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:58084 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389265AbgFWUPL (ORCPT ); Tue, 23 Jun 2020 16:15:11 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 80CCB2073E; Tue, 23 Jun 2020 20:15:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592943311; bh=OXoq7U7vrOFSjjoT5wdL3Gv4N5mXgeMwFrsSNSlyM4M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZBCVJ1yHWdVhcWzNttEJrd+mMsTN3OaIflHoycztBI3L0SJduA8Pa5nO0q2BoK7Qk 5kt4/N8StKznGS1kVQ9k7OiM0p/z9FLu3KGjIlOeAY/UTaTmGnFRlaNWwFeSztXXN8 ii7k0j+6iY7VIsC5YS60rGznCYQt6C+H1+9uKo3o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bob Peterson , Andreas Gruenbacher , Sasha Levin Subject: [PATCH 5.7 335/477] gfs2: fix use-after-free on transaction ail lists Date: Tue, 23 Jun 2020 21:55:32 +0200 Message-Id: <20200623195423.375999221@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195407.572062007@linuxfoundation.org> References: <20200623195407.572062007@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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 --- fs/gfs2/log.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 0644e58c6191b..b7a5221bea7d5 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -1003,8 +1003,10 @@ out: * @new: New transaction to be merged */ -static void gfs2_merge_trans(struct gfs2_trans *old, struct gfs2_trans *new) +static void gfs2_merge_trans(struct gfs2_sbd *sdp, struct gfs2_trans *new) { + struct gfs2_trans *old = sdp->sd_log_tr; + WARN_ON_ONCE(!test_bit(TR_ATTACHED, &old->tr_flags)); old->tr_num_buf_new += new->tr_num_buf_new; @@ -1016,6 +1018,11 @@ static void gfs2_merge_trans(struct gfs2_trans *old, struct gfs2_trans *new) list_splice_tail_init(&new->tr_databuf, &old->tr_databuf); list_splice_tail_init(&new->tr_buf, &old->tr_buf); + + spin_lock(&sdp->sd_ail_lock); + list_splice_tail_init(&new->tr_ail1_list, &old->tr_ail1_list); + list_splice_tail_init(&new->tr_ail2_list, &old->tr_ail2_list); + spin_unlock(&sdp->sd_ail_lock); } static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr) @@ -1027,7 +1034,7 @@ static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr) gfs2_log_lock(sdp); if (sdp->sd_log_tr) { - gfs2_merge_trans(sdp->sd_log_tr, tr); + gfs2_merge_trans(sdp, tr); } else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) { gfs2_assert_withdraw(sdp, test_bit(TR_ALLOCED, &tr->tr_flags)); sdp->sd_log_tr = tr; -- 2.25.1