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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31DC9C433FE for ; Mon, 27 Sep 2021 22:05:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1921560EB6 for ; Mon, 27 Sep 2021 22:05:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238301AbhI0WG4 (ORCPT ); Mon, 27 Sep 2021 18:06:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237771AbhI0WG3 (ORCPT ); Mon, 27 Sep 2021 18:06:29 -0400 Received: from bombadil.infradead.org (unknown [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1025DC051741; Mon, 27 Sep 2021 15:03:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=Uv9uzZRZiSomd0grs8gpdrysc8mwEPeeq1yOKtuyNSs=; b=ojHsK63rQcrDSP6Zl8+vCvLLDp BagSJfqBLadeXGg0SuCRifF8V56xO8gECSOiAS9K/nEYMc8T6WqTCqd7Tz6xLPnP2Lqy2zCWNiqnU 9zGbplsUrpJJuc3lEYAyyMYtQk9vZ4n/No9rKE4B/Xm3i6MR+jD1a9AzSEI5MoqeTHeqE5nijiPdb 6CUxnqps+E/dvWQdbEjy6XB6Le1x6c1O+M6XNbfEH/Auag7KzFKjymuKiZdiSz1M1S48rNOqI+uar x/OlwWdqqUv4JKa3GniY6WUXLxF6Gj0s3WWQh+SM1fbQ9x94uPCDZYge09rJWP1BnT8KhRlRMKIrG GH7DbNgA==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mUyiF-004VI5-Gm; Mon, 27 Sep 2021 22:03:03 +0000 From: Luis Chamberlain To: axboe@kernel.dk, efremov@linux.com, hch@lst.de Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Luis Chamberlain Subject: [PATCH v2 04/14] floppy: fix calling platform_device_unregister() on invalid drives Date: Mon, 27 Sep 2021 15:02:52 -0700 Message-Id: <20210927220302.1073499-5-mcgrof@kernel.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210927220302.1073499-1-mcgrof@kernel.org> References: <20210927220302.1073499-1-mcgrof@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: Luis Chamberlain Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org platform_device_unregister() should only be called when a respective platform_device_register() is called. However the floppy driver currently allows failures when registring a drive and a bail out could easily cause an invalid call to platform_device_unregister() where it was not intended. Fix this by adding a bool to keep track of when the platform device was registered for a drive. This does not fix any known panic / bug. This issue was found through code inspection while preparing the driver to use the up and coming support for device_add_disk() error handling. >From what I can tell from code inspection, chances of this ever happening should be insanely small, perhaps OOM. Signed-off-by: Luis Chamberlain --- drivers/block/floppy.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 9538146e520e..3592a6277d0b 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4478,6 +4478,7 @@ static const struct blk_mq_ops floppy_mq_ops = { }; static struct platform_device floppy_device[N_DRIVE]; +static bool registered[N_DRIVE]; static bool floppy_available(int drive) { @@ -4693,6 +4694,8 @@ static int __init do_floppy_init(void) if (err) goto out_remove_drives; + registered[drive] = true; + device_add_disk(&floppy_device[drive].dev, disks[drive][0], NULL); } @@ -4703,7 +4706,8 @@ static int __init do_floppy_init(void) while (drive--) { if (floppy_available(drive)) { del_gendisk(disks[drive][0]); - platform_device_unregister(&floppy_device[drive]); + if (registered[drive]) + platform_device_unregister(&floppy_device[drive]); } } out_release_dma: @@ -4946,7 +4950,8 @@ static void __exit floppy_module_exit(void) if (disks[drive][i]) del_gendisk(disks[drive][i]); } - platform_device_unregister(&floppy_device[drive]); + if (registered[drive]) + platform_device_unregister(&floppy_device[drive]); } for (i = 0; i < ARRAY_SIZE(floppy_type); i++) { if (disks[drive][i]) -- 2.30.2