From patchwork Wed Jul 8 16:25:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 11651895 X-Patchwork-Delegate: snitzer@redhat.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 20DEB14E3 for ; Wed, 8 Jul 2020 16:36:26 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CA23320663 for ; Wed, 8 Jul 2020 16:36:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="X7hZhG3k" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA23320663 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=dm-devel-bounces@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594226184; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=La68FdJQhALD3fntQXCDLR5jV+jMsdMnlVT02RZnDsk=; b=X7hZhG3k0XV7z0M3jfEx0nbk3ZT+mfTX9Yz9RJE2WOH0aRmS2QGX4qvdoFD9sRVrts+QJP Rw1ebbojTj50KgxTF4uKEWXa0qbrvrZvcvPLHPpJaFMUvUOTNp0Gvp8KNzvACDLDZDF7L7 ceQUaNPhYvzhwXuWjpRWghN3JasjOvE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-303-knHZhflaNiWYS8WRqfUv-A-1; Wed, 08 Jul 2020 12:36:22 -0400 X-MC-Unique: knHZhflaNiWYS8WRqfUv-A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9B8E88F6CC3; Wed, 8 Jul 2020 16:36:17 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B6365512FE; Wed, 8 Jul 2020 16:36:16 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id CF82972F7E; Wed, 8 Jul 2020 16:36:14 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 068GPN4l007108 for ; Wed, 8 Jul 2020 12:25:23 -0400 Received: by smtp.corp.redhat.com (Postfix) id C12E660F8D; Wed, 8 Jul 2020 16:25:23 +0000 (UTC) Delivered-To: dm-devel@redhat.com Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C19F960C80; Wed, 8 Jul 2020 16:25:20 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id 068GPK8u004243; Wed, 8 Jul 2020 12:25:20 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id 068GPKBm004239; Wed, 8 Jul 2020 12:25:20 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Wed, 8 Jul 2020 12:25:20 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Mike Snitzer Message-ID: User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-loop: dm-devel@redhat.com Cc: Tahsin Erdogan , dm-devel@redhat.com, Gabriel Krisman Bertazi , Khazhismel Kumykov Subject: [dm-devel] [PATCH] dm: use noio when sending kobject event X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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. This is the observed deadlock: iSCSI-write holding: rx_queue_mutex waiting: uevent_sock_mutex kobject_uevent_env+0x1bd/0x419 kobject_uevent+0xb/0xd device_add+0x48a/0x678 scsi_add_host_with_dma+0xc5/0x22d iscsi_host_add+0x53/0x55 iscsi_sw_tcp_session_create+0xa6/0x129 iscsi_if_rx+0x100/0x1247 netlink_unicast+0x213/0x4f0 netlink_sendmsg+0x230/0x3c0 iscsi_fail iscsi_conn_failure waiting: rx_queue_mutex schedule_preempt_disabled+0x325/0x734 __mutex_lock_slowpath+0x18b/0x230 mutex_lock+0x22/0x40 iscsi_conn_failure+0x42/0x149 worker_thread+0x24a/0xbc0 EventManager_ holding: uevent_sock_mutex waiting: dm_bufio_client->lock dm_bufio_lock+0xe/0x10 shrink+0x34/0xf7 shrink_slab+0x177/0x5d0 do_try_to_free_pages+0x129/0x470 try_to_free_mem_cgroup_pages+0x14f/0x210 memcg_kmem_newpage_charge+0xa6d/0x13b0 __alloc_pages_nodemask+0x4a3/0x1a70 fallback_alloc+0x1b2/0x36c __kmalloc_node_track_caller+0xb9/0x10d0 __alloc_skb+0x83/0x2f0 kobject_uevent_env+0x26b/0x419 dm_kobject_uevent+0x70/0x79 dev_suspend+0x1a9/0x1e7 ctl_ioctl+0x3e9/0x411 dm_ctl_ioctl+0x13/0x17 do_vfs_ioctl+0xb3/0x460 SyS_ioctl+0x5e/0x90 MemcgReclaimerD holding: dm_bufio_client->lock waiting: stuck io to finish (needs iscsi_fail thread to progress) schedule at ffffffffbd603618 io_schedule at ffffffffbd603ba4 do_io_schedule at ffffffffbdaf0d94 __wait_on_bit at ffffffffbd6008a6 out_of_line_wait_on_bit at ffffffffbd600960 wait_on_bit.constprop.10 at ffffffffbdaf0f17 __make_buffer_clean at ffffffffbdaf18ba __cleanup_old_buffer at ffffffffbdaf192f shrink at ffffffffbdaf19fd do_shrink_slab at ffffffffbd6ec000 shrink_slab at ffffffffbd6ec24a do_try_to_free_pages at ffffffffbd6eda09 try_to_free_mem_cgroup_pages at ffffffffbd6ede7e mem_cgroup_resize_limit at ffffffffbd7024c0 mem_cgroup_write at ffffffffbd703149 cgroup_file_write at ffffffffbd6d9c6e sys_write at ffffffffbd6662ea system_call_fastpath at ffffffffbdbc34a2 Signed-off-by: Mikulas Patocka Reported-by: Khazhismel Kumykov Reported-by: Tahsin Erdogan Reported-by: Gabriel Krisman Bertazi Cc: stable@vger.kernel.org Reviewed-by: Gabriel Krisman Bertazi --- drivers/md/dm.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel Index: linux-2.6/drivers/md/dm.c =================================================================== --- linux-2.6.orig/drivers/md/dm.c 2020-06-29 14:50:22.000000000 +0200 +++ linux-2.6/drivers/md/dm.c 2020-07-08 18:17:55.000000000 +0200 @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -2926,17 +2927,25 @@ 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)