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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 8F5BDC433DF for ; Thu, 18 Jun 2020 01:47:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6A6E32070A for ; Thu, 18 Jun 2020 01:47:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592444854; bh=IGcZDGzQwT8lDapCx09AldDJfWfNz+Syf1bWHEnISck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IKK7HFXCL+Qs/Tyeeambk1bgeG7rEO1jOZjzzoj8+dZFQOydTXRwZ0Kv3TKfURXet PBgL8v/s1Wj24Qb4QGCEGxaQqhZXXJz2i1Sybg935M2MDW2+oldusr6/6KOv0q3Bpy c/inJ+/TY08KdIP7tj5BokbVlWYLSLH6HW0O2rGk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733097AbgFRBrd (ORCPT ); Wed, 17 Jun 2020 21:47:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:36770 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732049AbgFRB2N (ORCPT ); Wed, 17 Jun 2020 21:28:13 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5DDCD2220B; Thu, 18 Jun 2020 01:28:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443693; bh=IGcZDGzQwT8lDapCx09AldDJfWfNz+Syf1bWHEnISck=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BdYpaK9QdpiC/mfXVaO/Xz01dCESmLDua47YylgMA4xPTQNT9T93rR9o03L39RkF/ bmgmV9fUnb4kAs69N9PNUniO+N5RDSXiF4SgEPl5hG3s90Xd12/nNaYyTjpnbg7rnW CpR3tFj2Ngaj7NRE3SOu8suPpd9C+ZmkUpoCXM98= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Bob Peterson , Andreas Gruenbacher , Sasha Levin , cluster-devel@redhat.com Subject: [PATCH AUTOSEL 4.14 104/108] gfs2: fix use-after-free on transaction ail lists Date: Wed, 17 Jun 2020 21:25:56 -0400 Message-Id: <20200618012600.608744-104-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618012600.608744-1-sashal@kernel.org> References: <20200618012600.608744-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 a3208511f35a..f30418911e1b 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -804,8 +804,10 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, * @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; @@ -817,6 +819,11 @@ 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) @@ -828,7 +835,7 @@ 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