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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,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 14C01C43441 for ; Mon, 19 Nov 2018 16:33:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB81620870 for ; Mon, 19 Nov 2018 16:33:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="o82WIat6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB81620870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731060AbeKTC5Z (ORCPT ); Mon, 19 Nov 2018 21:57:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:56048 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730241AbeKTC5Y (ORCPT ); Mon, 19 Nov 2018 21:57:24 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 7053920831; Mon, 19 Nov 2018 16:33:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542645195; bh=+RSRFg1EZe52AXA5yobu6EsLMMypl0TGtXAMpYZ3Gdc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o82WIat6ZwJA86ucqbIkatGNpHzqNs49CT7pk9KTWzSdc81JZ+nKr9rBRfCSoyzHn EbPPzMsMyeu1xfAOZby57r4s1Y0uJbYQlUwyGaXQZiClvrL4r+LI5ClHFBUEtyCrym khrOlbaR0PK1KNej0ZkAnmNTeJNiny3yAR8HXzWE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sergey Senozhatsky , Hannes Reinecke , Howard Chen , Minchan Kim , Sasha Levin Subject: [PATCH 4.19 073/205] zram: close udev startup race condition as default groups Date: Mon, 19 Nov 2018 17:26:20 +0100 Message-Id: <20181119162630.005323876@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162616.586062722@linuxfoundation.org> References: <20181119162616.586062722@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ commit fef912bf860e upstream. commit 98af4d4df889 upstream. I got a report from Howard Chen that he saw zram and sysfs race(ie, zram block device file is created but sysfs for it isn't yet) when he tried to create new zram devices via hotadd knob. v4.20 kernel fixes it by [1, 2] but it's too large size to merge into -stable so this patch fixes the problem by registering defualt group by Greg KH's approach[3]. This patch should be applied to every stable tree [3.16+] currently existing from kernel.org because the problem was introduced at 2.6.37 by [4]. [1] fef912bf860e, block: genhd: add 'groups' argument to device_add_disk [2] 98af4d4df889, zram: register default groups with device_add_disk() [3] http://kroah.com/log/blog/2013/06/26/how-to-create-a-sysfs-file-correctly/ [4] 33863c21e69e9, Staging: zram: Replace ioctls with sysfs interface Cc: Sergey Senozhatsky Cc: Hannes Reinecke Tested-by: Howard Chen Signed-off-by: Minchan Kim Reviewed-by: Hannes Reinecke Signed-off-by: Sasha Levin --- drivers/block/zram/zram_drv.c | 26 ++++++-------------------- 1 file changed, 6 insertions(+), 20 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index a1d6b5597c17..66921427d109 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1636,6 +1636,11 @@ static const struct attribute_group zram_disk_attr_group = { .attrs = zram_disk_attrs, }; +static const struct attribute_group *zram_disk_attr_groups[] = { + &zram_disk_attr_group, + NULL, +}; + /* * Allocate and initialize new zram device. the function returns * '>= 0' device_id upon success, and negative value otherwise. @@ -1716,24 +1721,15 @@ static int zram_add(void) zram->disk->queue->backing_dev_info->capabilities |= (BDI_CAP_STABLE_WRITES | BDI_CAP_SYNCHRONOUS_IO); + disk_to_dev(zram->disk)->groups = zram_disk_attr_groups; add_disk(zram->disk); - ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, - &zram_disk_attr_group); - if (ret < 0) { - pr_err("Error creating sysfs group for device %d\n", - device_id); - goto out_free_disk; - } strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor)); zram_debugfs_register(zram); pr_info("Added device: %s\n", zram->disk->disk_name); return device_id; -out_free_disk: - del_gendisk(zram->disk); - put_disk(zram->disk); out_free_queue: blk_cleanup_queue(queue); out_free_idr: @@ -1762,16 +1758,6 @@ static int zram_remove(struct zram *zram) mutex_unlock(&bdev->bd_mutex); zram_debugfs_unregister(zram); - /* - * Remove sysfs first, so no one will perform a disksize - * store while we destroy the devices. This also helps during - * hot_remove -- zram_reset_device() is the last holder of - * ->init_lock, no later/concurrent disksize_store() or any - * other sysfs handlers are possible. - */ - sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, - &zram_disk_attr_group); - /* Make sure all the pending I/O are finished */ fsync_bdev(bdev); zram_reset_device(zram); -- 2.17.1