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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B44A2ECAAA1 for ; Thu, 27 Oct 2022 17:00:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236790AbiJ0RAT (ORCPT ); Thu, 27 Oct 2022 13:00:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236768AbiJ0RAT (ORCPT ); Thu, 27 Oct 2022 13:00:19 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4026A53029 for ; Thu, 27 Oct 2022 10:00:17 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id ED4F3B82714 for ; Thu, 27 Oct 2022 17:00:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E3C5C433C1; Thu, 27 Oct 2022 17:00:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666890014; bh=ReqxKpjcJIP3mp6xJGfkWapq31FM37BsiH3/+pqB1nY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dmLzPM81k2UOAlQrkExTj3mWAICEa0GiiEOyJoFXoIokSd6hDQsDrLiwoekg0NbYf LcEfhTzy6U5Q94Z+ONDR02mARSQi7g3mANAMVsz/1rbW7NqdMwh5FsRyZpk7ReXYK/ X/fcnyLcEmo85zfnp4aTOVKDl2pPvFYIQIAp46j0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Christoph=20B=C3=B6hmwalder?= , Joel Colledge , Christoph Hellwig , Jens Axboe , Sasha Levin Subject: [PATCH 6.0 84/94] drbd: only clone bio if we have a backing device Date: Thu, 27 Oct 2022 18:55:26 +0200 Message-Id: <20221027165100.586052846@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221027165057.208202132@linuxfoundation.org> References: <20221027165057.208202132@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Christoph Böhmwalder [ Upstream commit 6d42ddf7f27b6723549ee6d4c8b1b418b59bf6b5 ] Commit c347a787e34cb (drbd: set ->bi_bdev in drbd_req_new) moved a bio_set_dev call (which has since been removed) to "earlier", from drbd_request_prepare to drbd_req_new. The problem is that this accesses device->ldev->backing_bdev, which is not NULL-checked at this point. When we don't have an ldev (i.e. when the DRBD device is diskless), this leads to a null pointer deref. So, only allocate the private_bio if we actually have a disk. This is also a small optimization, since we don't clone the bio to only to immediately free it again in the diskless case. Fixes: c347a787e34cb ("drbd: set ->bi_bdev in drbd_req_new") Co-developed-by: Christoph Böhmwalder Signed-off-by: Christoph Böhmwalder Co-developed-by: Joel Colledge Signed-off-by: Joel Colledge Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20221020085205.129090-1-christoph.boehmwalder@linbit.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/drbd/drbd_req.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 8f7f144e54f3..7f9bcc82fc9c 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -30,11 +30,6 @@ static struct drbd_request *drbd_req_new(struct drbd_device *device, struct bio return NULL; memset(req, 0, sizeof(*req)); - req->private_bio = bio_alloc_clone(device->ldev->backing_bdev, bio_src, - GFP_NOIO, &drbd_io_bio_set); - req->private_bio->bi_private = req; - req->private_bio->bi_end_io = drbd_request_endio; - req->rq_state = (bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0) | (bio_op(bio_src) == REQ_OP_WRITE_ZEROES ? RQ_ZEROES : 0) | (bio_op(bio_src) == REQ_OP_DISCARD ? RQ_UNMAP : 0); @@ -1219,9 +1214,12 @@ drbd_request_prepare(struct drbd_device *device, struct bio *bio) /* Update disk stats */ req->start_jif = bio_start_io_acct(req->master_bio); - if (!get_ldev(device)) { - bio_put(req->private_bio); - req->private_bio = NULL; + if (get_ldev(device)) { + req->private_bio = bio_alloc_clone(device->ldev->backing_bdev, + bio, GFP_NOIO, + &drbd_io_bio_set); + req->private_bio->bi_private = req; + req->private_bio->bi_end_io = drbd_request_endio; } /* process discards always from our submitter thread */ -- 2.35.1