From patchwork Mon Dec 28 12:50:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 355077 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, USER_AGENT_GIT autolearn=unavailable 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 7D13AC43332 for ; Mon, 28 Dec 2020 13:36:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6154022D0A for ; Mon, 28 Dec 2020 13:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389462AbgL1Nfu (ORCPT ); Mon, 28 Dec 2020 08:35:50 -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 S2389458AbgL1Nfu (ORCPT ); Mon, 28 Dec 2020 08:35:50 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 46B3A21D94; Mon, 28 Dec 2020 13:35:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609162509; bh=nZMrMAamCH8fxLv4x7n/eb5SNkknL3x8hgvUN8jEIWo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vVmxu1f3ekA6dFu86AtSsfSXs1sMRD4rnFsgKKZkuLreIUZaXQQyhWiJqM6fz9tKz k+GOpctX8x92+Kz04pxlyp2r89ZLos66MS/cju8hu2hxOwEpDloa7yzgL35aou0gTK jC19mL6ff8GMybPnta9rGKyTJSyvD0x2vxnMik7g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefan Haberland , Jan Hoeppner , Jens Axboe Subject: [PATCH 4.19 283/346] s390/dasd: fix list corruption of pavgroup group list Date: Mon, 28 Dec 2020 13:50:02 +0100 Message-Id: <20201228124933.460267821@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124919.745526410@linuxfoundation.org> References: <20201228124919.745526410@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Stefan Haberland commit 0ede91f83aa335da1c3ec68eb0f9e228f269f6d8 upstream. dasd_alias_add_device() moves devices to the active_devices list in case of a scheduled LCU update regardless if they have previously been in a pavgroup or not. Example: device A and B are in the same pavgroup. Device A has already been in a pavgroup and the private->pavgroup pointer is set and points to a valid pavgroup. While going through dasd_add_device it is moved from the pavgroup to the active_devices list. In parallel device B might be removed from the same pavgroup in remove_device_from_lcu() which in turn checks if the group is empty and deletes it accordingly because device A has already been removed from there. When now device A enters remove_device_from_lcu() it is tried to remove it from the pavgroup again because the pavgroup pointer is still set and again the empty group will be cleaned up which leads to a list corruption. Fix by setting private->pavgroup to NULL in dasd_add_device. If the device has been the last device on the pavgroup an empty pavgroup remains but this will be cleaned up by the scheduled lcu_update which iterates over all existing pavgroups. Fixes: 8e09f21574ea ("[S390] dasd: add hyper PAV support to DASD device driver, part 1") Cc: stable@vger.kernel.org Signed-off-by: Stefan Haberland Reviewed-by: Jan Hoeppner Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/s390/block/dasd_alias.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/s390/block/dasd_alias.c +++ b/drivers/s390/block/dasd_alias.c @@ -642,6 +642,7 @@ int dasd_alias_add_device(struct dasd_de } if (lcu->flags & UPDATE_PENDING) { list_move(&device->alias_list, &lcu->active_devices); + private->pavgroup = NULL; _schedule_lcu_update(lcu, device); } spin_unlock_irqrestore(&lcu->lock, flags);