From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755374Ab3GULwX (ORCPT ); Sun, 21 Jul 2013 07:52:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45090 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754353Ab3GULwW (ORCPT ); Sun, 21 Jul 2013 07:52:22 -0400 Date: Sun, 21 Jul 2013 14:52:16 +0300 From: Gleb Natapov To: Steven Rostedt Cc: linux-kernel@vger.kernel.org Subject: module unloading hangs after using ftrace with 3.11.0-rc1 Message-ID: <20130721115215.GG20379@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steven, After tracing KVM using trace-cmd with kvm trace points enables I tried to unload kvm modules and rmmod hanged in tracing_reset_all_online_cpus: [ 1234.665038] rmmod D 00000000ffffffff 0 7819 7664 0x00000000 [ 1234.665038] ffff880129661d38 0000000000000086 ffff880374c7b4d0 ffff880129661fd8 [ 1234.665038] 0000000000004000 0000000000012a40 ffff88017af63180 ffff880179fe3180 [ 1234.665038] ffff880129661c78 ffffffff810ad4f9 0000000000000008 0000000000000002 [ 1234.665038] Call Trace: [ 1234.665038] [] ? rcu_is_cpu_idle+0x38/0x57 [ 1234.665038] [] ? d_set_d_op+0xb5/0xb5 [ 1234.665038] [] schedule+0x64/0x66 [ 1234.665038] [] schedule_preempt_disabled+0x18/0x24 [ 1234.665038] [] __mutex_lock_slowpath+0x156/0x1c2 [ 1234.665038] [] mutex_lock+0x18/0x29 [ 1234.665038] [] tracing_reset_all_online_cpus+0x12/0x49 [ 1234.665038] [] trace_module_notify+0x27b/0x2a2 [ 1234.665038] [] notifier_call_chain+0x37/0x63 [ 1234.665038] [] __blocking_notifier_call_chain+0x4b/0x60 [ 1234.665038] [] blocking_notifier_call_chain+0x14/0x16 [ 1234.665038] [] SyS_delete_module+0x228/0x274 [ 1234.665038] [] system_call_fastpath+0x16/0x1b I haven't verified how reproducible this is yet. -- Gleb.