From patchwork Tue Oct 17 18:48:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13425714 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5B849CA5B for ; Tue, 17 Oct 2023 18:48:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="UYWaETAj" Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0F43D3; Tue, 17 Oct 2023 11:48:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=cl8di6G3DxLLFf5MtSBQgO7MOKUrZZ/L+falVxOQuKg=; b=UYWaETAjbVF1TF5AWFnEd2BOv1 UYLxmX1xpq33/xS5o+//DLjuFFRDybdy6/xDYyukec8TdQo1RhAHTXlBwSR4HLxpakXzKc6KCGhIZ TtYs/1Izxqoqt1KutZNfApLPSUQpUhf5rSRksn+sJ7hpgnLU/FSDAo3gSlKmcpMVHxZ6b3VXKegSx on7F9aMyj+JdT73fT827+VJ0t0qMOzljjgz5quwpQxfRTCaqW0QeEO+Q18/QOp73uoByRImHln4/S 9pIsPL/RmV+Mmmma1r8dEhrcRDTTJxjDdVdChuGWFQuPk9e4SkhzE1CYB28dg6RIV3IzoNZS/dpiQ 0zysKpyA==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qsp7P-00D0Le-0h; Tue, 17 Oct 2023 18:48:39 +0000 From: Christoph Hellwig To: Christian Brauner , Al Viro , Jens Axboe Cc: Jan Kara , Denis Efremov , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 4/5] block: assert that we're not holding open_mutex over blk_report_disk_dead Date: Tue, 17 Oct 2023 20:48:22 +0200 Message-Id: <20231017184823.1383356-5-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231017184823.1383356-1-hch@lst.de> References: <20231017184823.1383356-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net From: Christian Brauner blk_report_disk_dead() has the following major callers: (1) del_gendisk() (2) blk_mark_disk_dead() Since del_gendisk() acquires disk->open_mutex it's clear that all callers are assumed to be called without disk->open_mutex held. In turn, blk_report_disk_dead() is called without disk->open_mutex held in del_gendisk(). All callers of blk_mark_disk_dead() call it without disk->open_mutex as well. Ensure that it is clear that blk_report_disk_dead() is called without disk->open_mutex on purpose by asserting it and a comment in the code. Signed-off-by: Christian Brauner Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Reviewed-by: Jan Kara --- block/genhd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/block/genhd.c b/block/genhd.c index 4a16a424f57d4f..c9d06f72c587e8 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -559,6 +559,13 @@ static void blk_report_disk_dead(struct gendisk *disk, bool surprise) struct block_device *bdev; unsigned long idx; + /* + * On surprise disk removal, bdev_mark_dead() may call into file + * systems below. Make it clear that we're expecting to not hold + * disk->open_mutex. + */ + lockdep_assert_not_held(&disk->open_mutex); + rcu_read_lock(); xa_for_each(&disk->part_tbl, idx, bdev) { if (!kobject_get_unless_zero(&bdev->bd_device.kobj))