From patchwork Wed Sep 5 13:17:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 10588855 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 62C065A4 for ; Wed, 5 Sep 2018 13:17:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4E5B92A05B for ; Wed, 5 Sep 2018 13:17:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3FFE82A070; Wed, 5 Sep 2018 13:17:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C8DD32A05B for ; Wed, 5 Sep 2018 13:17:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726909AbeIERsC (ORCPT ); Wed, 5 Sep 2018 13:48:02 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:55690 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725900AbeIERsC (ORCPT ); Wed, 5 Sep 2018 13:48:02 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2B6EF85760; Wed, 5 Sep 2018 13:17:48 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3B5931007242; Wed, 5 Sep 2018 13:17:46 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id w85DHkkS030114; Wed, 5 Sep 2018 09:17:46 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id w85DHjmb030110; Wed, 5 Sep 2018 09:17:45 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Wed, 5 Sep 2018 09:17:45 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Mike Snitzer cc: dm-devel@redhat.com, linux-crypto@vger.kernel.org, Herbert Xu , peter.klotz99@gmail.com, david@fromorbit.com Subject: [PATCH] dm-crypt and dm-integrity: disable CRYPTO_TFM_REQ_MAY_SLEEP to fix a deadlock Message-ID: User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 05 Sep 2018 13:17:48 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 05 Sep 2018 13:17:48 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mpatocka@redhat.com' RCPT:'' Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There's a deadlock reported here: https://bugzilla.kernel.org/show_bug.cgi?id=200835 * dm-crypt calls crypt_convert in xts mode * init_crypt from xts.c calls kmalloc(GFP_KERNEL) * kmalloc(GFP_KERNEL) recurses into the XFS filesystem, the filesystem tries to submit some bios and wait for them, causing a deadlock This patch drops the flag CRYPTO_TFM_REQ_MAY_SLEEP, which will change the allocation from GFP_KERNEL to GFP_ATOMIC, therefore it can't recurse into a filesystem. The GFP_ATOMIC allocation can fail, but the function init_crypt in xts.c handles the allocation failure gracefully - it will fall back to preallocated buffer in the allocation fails. The crypto API maintainer says that the crypto API only needs to allocate memory when dealing with unaligned buffers and therefore turning CRYPTO_TFM_REQ_MAY_SLEEP off is safe (see this discussion: https://www.redhat.com/archives/dm-devel/2018-August/msg00195.html ) Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org --- drivers/md/dm-crypt.c | 10 +++++----- drivers/md/dm-integrity.c | 4 ++-- 2 files changed, 7 insertions(+), 7 deletions(-) Index: linux-2.6/drivers/md/dm-crypt.c =================================================================== --- linux-2.6.orig/drivers/md/dm-crypt.c 2018-09-03 18:17:44.190000000 +0200 +++ linux-2.6/drivers/md/dm-crypt.c 2018-09-04 21:36:58.460000000 +0200 @@ -332,7 +332,7 @@ static int crypt_iv_essiv_init(struct cr int err; desc->tfm = essiv->hash_tfm; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->flags = 0; err = crypto_shash_digest(desc, cc->key, cc->key_size, essiv->salt); shash_desc_zero(desc); @@ -606,7 +606,7 @@ static int crypt_iv_lmk_one(struct crypt int i, r; desc->tfm = lmk->hash_tfm; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->flags = 0; r = crypto_shash_init(desc); if (r) @@ -768,7 +768,7 @@ static int crypt_iv_tcw_whitening(struct /* calculate crc32 for every 32bit part and xor it */ desc->tfm = tcw->crc32_tfm; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->flags = 0; for (i = 0; i < 4; i++) { r = crypto_shash_init(desc); if (r) @@ -1251,7 +1251,7 @@ static void crypt_alloc_req_skcipher(str * requests if driver request queue is full. */ skcipher_request_set_callback(ctx->r.req, - CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, + CRYPTO_TFM_REQ_MAY_BACKLOG, kcryptd_async_done, dmreq_of_req(cc, ctx->r.req)); } @@ -1268,7 +1268,7 @@ static void crypt_alloc_req_aead(struct * requests if driver request queue is full. */ aead_request_set_callback(ctx->r.req_aead, - CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, + CRYPTO_TFM_REQ_MAY_BACKLOG, kcryptd_async_done, dmreq_of_req(cc, ctx->r.req_aead)); } Index: linux-2.6/drivers/md/dm-integrity.c =================================================================== --- linux-2.6.orig/drivers/md/dm-integrity.c 2018-09-03 18:17:44.180000000 +0200 +++ linux-2.6/drivers/md/dm-integrity.c 2018-09-04 21:37:41.230000000 +0200 @@ -532,7 +532,7 @@ static void section_mac(struct dm_integr unsigned j, size; desc->tfm = ic->journal_mac; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->flags = 0; r = crypto_shash_init(desc); if (unlikely(r)) { @@ -676,7 +676,7 @@ static void complete_journal_encrypt(str static bool do_crypt(bool encrypt, struct skcipher_request *req, struct journal_completion *comp) { int r; - skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, + skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, complete_journal_encrypt, comp); if (likely(encrypt)) r = crypto_skcipher_encrypt(req);