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=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 DA0C7C43603 for ; Tue, 10 Dec 2019 21:38:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9938D20828 for ; Tue, 10 Dec 2019 21:38:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576013910; bh=+mJtfdZ/m/8YdlF0bimkvFs+ZilsuQaB+cO9fGqJGZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aSoMbMlprL5QL6PvCH8ohhJhSRbtGiYseZp1xxrXx+pYQkPvkpAUsQmsJrUP7AB28 3yZMbxbvN6IyukzaQh2MybsCLYxKrOGypJt5ZFwyoDai3n05LtaO83YqoNs+Z41cy2 WmlcyXigamCSoJr7PJxQ5k+sDL7DqzI/P57eNdZ4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729676AbfLJVi3 (ORCPT ); Tue, 10 Dec 2019 16:38:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:40906 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730209AbfLJVfQ (ORCPT ); Tue, 10 Dec 2019 16:35:16 -0500 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 ED98E24655; Tue, 10 Dec 2019 21:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576013715; bh=+mJtfdZ/m/8YdlF0bimkvFs+ZilsuQaB+cO9fGqJGZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B8aq5sbtNpniErcGYMxmZNJNT+s8QXptbk8ovQGP2P2Ep6QwrjeYAX7ghDqwHspOq k5cZ9fEHaS+VjEAvWhEGEYhu8MuB7NNUOd+8vRhDIShSHxHJR7BwApuElwJyWaUphm ZKPwa95U2r9/cau97hpw0VAex6M0ne2nXO81nU7o= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Coly Li , Dan Carpenter , Jens Axboe , Sasha Levin , linux-bcache@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 143/177] bcache: fix static checker warning in bcache_device_free() Date: Tue, 10 Dec 2019 16:31:47 -0500 Message-Id: <20191210213221.11921-143-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210213221.11921-1-sashal@kernel.org> References: <20191210213221.11921-1-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: Coly Li [ Upstream commit 2d8869518a525c9bce5f5268419df9dfbe3dfdeb ] Commit cafe56359144 ("bcache: A block layer cache") leads to the following static checker warning: ./drivers/md/bcache/super.c:770 bcache_device_free() warn: variable dereferenced before check 'd->disk' (see line 766) drivers/md/bcache/super.c 762 static void bcache_device_free(struct bcache_device *d) 763 { 764 lockdep_assert_held(&bch_register_lock); 765 766 pr_info("%s stopped", d->disk->disk_name); ^^^^^^^^^ Unchecked dereference. 767 768 if (d->c) 769 bcache_device_detach(d); 770 if (d->disk && d->disk->flags & GENHD_FL_UP) ^^^^^^^ Check too late. 771 del_gendisk(d->disk); 772 if (d->disk && d->disk->queue) 773 blk_cleanup_queue(d->disk->queue); 774 if (d->disk) { 775 ida_simple_remove(&bcache_device_idx, 776 first_minor_to_idx(d->disk->first_minor)); 777 put_disk(d->disk); 778 } 779 It is not 100% sure that the gendisk struct of bcache device will always be there, the warning makes sense when there is problem in block core. This patch tries to remove the static checking warning by checking d->disk to avoid NULL pointer deferences. Reported-by: Dan Carpenter Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/md/bcache/super.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 14d381cc6d747..2d60bcdb5b9c1 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -747,20 +747,28 @@ static inline int idx_to_first_minor(int idx) static void bcache_device_free(struct bcache_device *d) { + struct gendisk *disk = d->disk; + lockdep_assert_held(&bch_register_lock); - pr_info("%s stopped", d->disk->disk_name); + if (disk) + pr_info("%s stopped", disk->disk_name); + else + pr_err("bcache device (NULL gendisk) stopped"); if (d->c) bcache_device_detach(d); - if (d->disk && d->disk->flags & GENHD_FL_UP) - del_gendisk(d->disk); - if (d->disk && d->disk->queue) - blk_cleanup_queue(d->disk->queue); - if (d->disk) { + + if (disk) { + if (disk->flags & GENHD_FL_UP) + del_gendisk(disk); + + if (disk->queue) + blk_cleanup_queue(disk->queue); + ida_simple_remove(&bcache_device_idx, - first_minor_to_idx(d->disk->first_minor)); - put_disk(d->disk); + first_minor_to_idx(disk->first_minor)); + put_disk(disk); } bioset_exit(&d->bio_split); -- 2.20.1