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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 DE295C433E4 for ; Tue, 14 Jul 2020 18:48:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BAC3022B2A for ; Tue, 14 Jul 2020 18:48:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752480; bh=pHJxLikuzUBUsmeFUYG5PrZJTGqQpdsm39r3eU+a4b4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=a4QyxQBo94ThZvckNaq0md/17i3P1IRTUpkiv609SuLMA8PP7KLAAJHm1RHzKFlXJ 6MH3vQb9tLfA1vFx+sV/XaOnBv50uguCX4tgdTpCYCEoLkpTc5uClxWWbIPWapXNvs gifZM6xXR1QThNNt70626jOtzKv5m66RZLOgz9QE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729866AbgGNSr7 (ORCPT ); Tue, 14 Jul 2020 14:47:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:43204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729854AbgGNSr5 (ORCPT ); Tue, 14 Jul 2020 14:47:57 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 CFE8322AB0; Tue, 14 Jul 2020 18:47:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752476; bh=pHJxLikuzUBUsmeFUYG5PrZJTGqQpdsm39r3eU+a4b4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g+hQ1UswJksIMLwVFYwpnAgRmCObEVew9U1t60i/dkLImMvQhoWIbIgiz7ex51kPR xkzgp9YMTeFauDptbGYcjRRCihzsTpATX9UkL6bzxbCvnLbfdirEOMSe6Sm+woZABB hqow2XqPPMBfGs+kAQSqqpCEs0Qr7NVFCH0EHWj8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Khazhismel Kumykov , Tahsin Erdogan , Gabriel Krisman Bertazi , Mikulas Patocka , Mike Snitzer Subject: [PATCH 4.19 55/58] dm: use noio when sending kobject event Date: Tue, 14 Jul 2020 20:44:28 +0200 Message-Id: <20200714184058.910142747@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184056.149119318@linuxfoundation.org> References: <20200714184056.149119318@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Mikulas Patocka commit 6958c1c640af8c3f40fa8a2eee3b5b905d95b677 upstream. kobject_uevent may allocate memory and it may be called while there are dm devices suspended. The allocation may recurse into a suspended device, causing a deadlock. We must set the noio flag when sending a uevent. The observed deadlock was reported here: https://www.redhat.com/archives/dm-devel/2020-March/msg00025.html Reported-by: Khazhismel Kumykov Reported-by: Tahsin Erdogan Reported-by: Gabriel Krisman Bertazi Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -2853,17 +2854,25 @@ EXPORT_SYMBOL_GPL(dm_internal_resume_fas int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action, unsigned cookie) { + int r; + unsigned noio_flag; char udev_cookie[DM_COOKIE_LENGTH]; char *envp[] = { udev_cookie, NULL }; + noio_flag = memalloc_noio_save(); + if (!cookie) - return kobject_uevent(&disk_to_dev(md->disk)->kobj, action); + r = kobject_uevent(&disk_to_dev(md->disk)->kobj, action); else { snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", DM_COOKIE_ENV_VAR_NAME, cookie); - return kobject_uevent_env(&disk_to_dev(md->disk)->kobj, - action, envp); + r = kobject_uevent_env(&disk_to_dev(md->disk)->kobj, + action, envp); } + + memalloc_noio_restore(noio_flag); + + return r; } uint32_t dm_next_uevent_seq(struct mapped_device *md)