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 AC46EC43441 for ; Mon, 26 Nov 2018 10:53:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7425C20817 for ; Mon, 26 Nov 2018 10:53:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="OvbH3E7u" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7425C20817 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 S1726955AbeKZVrT (ORCPT ); Mon, 26 Nov 2018 16:47:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:55448 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726138AbeKZVrS (ORCPT ); Mon, 26 Nov 2018 16:47:18 -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 2B3B020817; Mon, 26 Nov 2018 10:53:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543229614; bh=0MQbv3WXR/R3/X33pXmulC2zlkk5xZSAzFCiLPnoP48=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OvbH3E7uQp/fDF4+3vUb9pYXK00xZbrz+14jBEPv6jLKHgQcyHKPjEnU1/ostisE8 peAbGkAtgGN3oqVusuBrQxOsbEME94k8oms+63U3d3z9rXrRKG+CpEwVBb7DghoLzF fSQv7qVtaSlvBIzYeWAJW+lx17qXZ2FkECAV35NM= 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 3.18 11/24] zram: close udev startup race condition as default groups Date: Mon, 26 Nov 2018 11:51:05 +0100 Message-Id: <20181126105031.483289228@linuxfoundation.org> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181126105029.790599475@linuxfoundation.org> References: <20181126105029.790599475@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 3.18-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 Signed-off-by: Sasha Levin --- drivers/block/zram/zram_drv.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 7e94459a489a..5f4e6a3c2dde 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -999,6 +999,11 @@ static 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, +}; + static int create_device(struct zram *zram, int device_id) { int ret = -ENOMEM; @@ -1060,22 +1065,14 @@ static int create_device(struct zram *zram, int device_id) zram->disk->queue->limits.discard_zeroes_data = 0; queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue); + 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_warn("Error creating sysfs group"); - goto out_free_disk; - } strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor)); zram->meta = NULL; zram->max_comp_streams = 1; return 0; -out_free_disk: - del_gendisk(zram->disk); - put_disk(zram->disk); out_free_queue: blk_cleanup_queue(zram->queue); out: @@ -1084,9 +1081,6 @@ out: static void destroy_device(struct zram *zram) { - sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, - &zram_disk_attr_group); - del_gendisk(zram->disk); put_disk(zram->disk); -- 2.17.1