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=-9.8 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=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 04B93C2D0CE for ; Sun, 29 Dec 2019 18:03:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFE3B207FF for ; Sun, 29 Dec 2019 18:03:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577642619; bh=g3Nn7L7C/8x8ErY7HygVtpVdgu4hSNlrNH+FME2Vqpo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=saNadISh/EphUHcuzi6bZdluoM+BYAUec2yNHC72rtdUlS3pTHnixaBnfsQ7LCoNl O/cpZiUo4jJ9iNdk/H4VprNntxzXhTGG1rEHVOlsuXZIJDM5XdW5wAofhbbe2Pu4oL Znw4hJI3ZgDSrUnbC9sHHfguQI6T/AIjiXFGklFY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732432AbfL2RxQ (ORCPT ); Sun, 29 Dec 2019 12:53:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:40092 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732429AbfL2RxQ (ORCPT ); Sun, 29 Dec 2019 12:53:16 -0500 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 D5804206DB; Sun, 29 Dec 2019 17:53:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577641995; bh=g3Nn7L7C/8x8ErY7HygVtpVdgu4hSNlrNH+FME2Vqpo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VTngj9R7f0diMclRRl4RBm3lWcuwZlpSw32x1slPDBuyYex6WMKMiHxd7W1k5Xlqc aTUrwvZZS+5NkUhwTFwT2t+H0ZP+AG/HXfc0IDbVq7zYFXTtDqXfLjW0V4NbcSmT2w ZSD0TSbJYsaspgeFmFeWkckCqZCcy2GPIAmZThPU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Coly Li , Jens Axboe , Sasha Levin Subject: [PATCH 5.4 298/434] bcache: fix static checker warning in bcache_device_free() Date: Sun, 29 Dec 2019 18:25:51 +0100 Message-Id: <20191229172721.745706720@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191229172702.393141737@linuxfoundation.org> References: <20191229172702.393141737@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: 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 20ed838e9413..d2654880b7b9 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -761,20 +761,28 @@ 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