From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:34474 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754804Ab3GQNqe (ORCPT ); Wed, 17 Jul 2013 09:46:34 -0400 Date: Wed, 17 Jul 2013 09:47:01 -0400 From: Jeff Layton To: Johannes Berg Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Subject: hung task while plugging in cfg80211 Message-ID: <20130717094701.03624329@corrin.poochiereds.net> (sfid-20130717_154704_056473_9F59DC01) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-wireless-owner@vger.kernel.org List-ID: (Resending with wider distribution list since my earlier email to linux-wireless didn't get a response) I updated the kernel on my fedora rawhide KVM guest, and noticed that the ethernet interface wasn't coming up at all. While poking around, I saw this stack trace pop up: Jul 12 07:29:25 rawhide kernel: [ 241.156196] INFO: task modprobe:501 blocked for more than 120 seconds. Jul 12 07:29:25 rawhide kernel: [ 241.157222] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Jul 12 07:29:25 rawhide kernel: [ 241.158379] modprobe D ffff880118c526e0 4584 501 500 0x00000080 Jul 12 07:29:25 rawhide kernel: [ 241.159458] ffff8800d10c3ba8 0000000000000046 00000000001d5300 ffff8800d10c3fd8 Jul 12 07:29:25 rawhide kernel: [ 241.160644] ffff8800d10c3fd8 00000000001d5300 ffff8800d2ae4dc0 ffff8800d2ae4dc0 Jul 12 07:29:25 rawhide kernel: [ 241.161875] ffffffff81d0bfa0 ffffffff81d0bfa8 ffffffff00000000 ffffffff81d0bff0 Jul 12 07:29:25 rawhide kernel: [ 241.163096] Call Trace: Jul 12 07:29:25 rawhide kernel: [ 241.163460] [] schedule+0x29/0x70 Jul 12 07:29:25 rawhide kernel: [ 241.164235] [] rwsem_down_write_failed+0xed/0x1a0 Jul 12 07:29:25 rawhide kernel: [ 241.165489] [] ? update_cpu_load_active+0xb0/0xb0 Jul 12 07:29:25 rawhide kernel: [ 241.166267] [] call_rwsem_down_write_failed+0x13/0x20 Jul 12 07:29:25 rawhide kernel: [ 241.166760] [] ? down_write+0x9d/0xb2 Jul 12 07:29:25 rawhide kernel: [ 241.167189] [] ? genl_lock_all+0x15/0x30 Jul 12 07:29:25 rawhide kernel: [ 241.167603] [] genl_lock_all+0x15/0x30 Jul 12 07:29:25 rawhide kernel: [ 241.168036] [] genl_register_family+0x53/0x1f0 Jul 12 07:29:25 rawhide kernel: [ 241.168490] [] ? 0xffffffffa015dfff Jul 12 07:29:25 rawhide kernel: [ 241.168877] [] genl_register_family_with_ops+0x20/0x80 Jul 12 07:29:25 rawhide kernel: [ 241.169406] [] ? 0xffffffffa015dfff Jul 12 07:29:25 rawhide kernel: [ 241.169802] [] nl80211_init+0x24/0xf0 [cfg80211] Jul 12 07:29:25 rawhide kernel: [ 241.170297] [] ? 0xffffffffa015dfff Jul 12 07:29:25 rawhide kernel: [ 241.170686] [] cfg80211_init+0x43/0xdb [cfg80211] Jul 12 07:29:25 rawhide kernel: [ 241.171230] [] do_one_initcall+0xfa/0x1b0 Jul 12 07:29:25 rawhide kernel: [ 241.171651] [] ? set_memory_nx+0x43/0x50 Jul 12 07:29:25 rawhide kernel: [ 241.172099] [] load_module+0x1c6f/0x27f0 Jul 12 07:29:25 rawhide kernel: [ 241.172515] [] ? store_uevent+0x40/0x40 Jul 12 07:29:25 rawhide kernel: [ 241.172933] [] SyS_finit_module+0x86/0xb0 Jul 12 07:29:25 rawhide kernel: [ 241.173379] [] system_call_fastpath+0x16/0x1b ...on a hunch, I blacklisted the cfg80211 module, and that seems to have worked around the problem for now. I suspect that NM was trying to plug in this module and it hung, and it couldn't proceed any further to configure the virtual ethernet interface. In the fedora rawhide kernels, last known good one is kernel-3.11.0-0.rc0.git3.1.fc20, and bad one is kernel-3.11.0-0.rc0.git6.1.fc20. I haven't bisected it further. -- Jeff Layton