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=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 733CAC2D0CE for ; Sun, 29 Dec 2019 17:38:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E321206CB for ; Sun, 29 Dec 2019 17:38:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577641130; bh=c15sxyYB7SoT9Non22x2h0tkHHoK/8IWuGc80z7r14I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0hCcjE8fSd7aRndsZU2YL2I0Eq4jdu9XIED/zK/B0cH7KrRnitjn1uGIGaSQgJwIq p72zdb1wfKaHdWb5/HMuZhxW52qP+fVVuTaPQkYN04RjljvGmJNdJte5v9yl8dkUX+ s4hlbD6gK6KAGNj4g6tyCTj5SxkSnF2n0bDA6olk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729826AbfL2Rit (ORCPT ); Sun, 29 Dec 2019 12:38:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:36214 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729521AbfL2Rdx (ORCPT ); Sun, 29 Dec 2019 12:33:53 -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 4615C20722; Sun, 29 Dec 2019 17:33:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577640832; bh=c15sxyYB7SoT9Non22x2h0tkHHoK/8IWuGc80z7r14I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aPkzb87b2jBEzBJrZySSHVUUqY3+IzuK+b61fTAIHOp33r0LhCNArt0QvVOi00GJb oDxGWxKKKGJKBgj6MrLGHpJmtdUWL1qNhS48BtIBnA+95C3+WxTi4bKaAXNGsVAd7L sM8YoTBTq9jSBGxYCaW1DeMhvV8yXjh050Uu1iB0= 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 4.19 157/219] bcache: fix static checker warning in bcache_device_free() Date: Sun, 29 Dec 2019 18:19:19 +0100 Message-Id: <20191229162532.327225338@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191229162508.458551679@linuxfoundation.org> References: <20191229162508.458551679@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 14d381cc6d74..2d60bcdb5b9c 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