From patchwork Mon Dec 28 12:50:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353189 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 C9713C433DB for ; Mon, 28 Dec 2020 15:58:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98C1D207CF for ; Mon, 28 Dec 2020 15:58:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391105AbgL1Nd6 (ORCPT ); Mon, 28 Dec 2020 08:33:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:34406 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390196AbgL1Nd5 (ORCPT ); Mon, 28 Dec 2020 08:33:57 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3B096205CB; Mon, 28 Dec 2020 13:33:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609162396; bh=hZO3f+sU8DLpmWcx9RIoRxYScZUiG1znp4VtXoefxS8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ym3wKp1YEBhvY6bZ7MvLwTV1RpjjWHNjwWtWx51sBR2T/VqlUbBXJm/zoSo1QMo5G Q0aClyolWUDHKCeUnoIToXQhQ6kpIlZ4y9q26PqpgGCuDLc0JAapsBpVgDG3x1S9/4 of0SnnVQIKhSb62pucV/3UXT2/EYWMiWccHUgqnE= 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 4.19 284/346] s390/dasd: fix list corruption of lcu list Date: Mon, 28 Dec 2020 13:50:03 +0100 Message-Id: <20201228124933.508133620@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 53a7f655834c7c335bf683f248208d4fbe4b47bc upstream. In dasd_alias_disconnect_device_from_lcu the device is removed from any list on the LCU. Afterwards the LCU is removed from the lcu list if it does not contain devices any longer. The lcu->lock protects the lcu from parallel updates. But to cancel all workers and wait for completion the lcu->lock has to be unlocked. If two devices are removed in parallel and both are removed from the LCU the first device that takes the lcu->lock again will delete the LCU because it is already empty but the second device also tries to free the LCU which leads to a list corruption of the lcu list. Fix by removing the device right before the lcu is checked without unlocking the lcu->lock in between. 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 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/s390/block/dasd_alias.c +++ b/drivers/s390/block/dasd_alias.c @@ -256,7 +256,6 @@ void dasd_alias_disconnect_device_from_l return; device->discipline->get_uid(device, &uid); spin_lock_irqsave(&lcu->lock, flags); - list_del_init(&device->alias_list); /* make sure that the workers don't use this device */ if (device == lcu->suc_data.device) { spin_unlock_irqrestore(&lcu->lock, flags); @@ -283,6 +282,7 @@ void dasd_alias_disconnect_device_from_l spin_lock_irqsave(&aliastree.lock, flags); spin_lock(&lcu->lock); + list_del_init(&device->alias_list); if (list_empty(&lcu->grouplist) && list_empty(&lcu->active_devices) && list_empty(&lcu->inactive_devices)) {