From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755606Ab3AVEDq (ORCPT ); Mon, 21 Jan 2013 23:03:46 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:25327 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752307Ab3AVEDo (ORCPT ); Mon, 21 Jan 2013 23:03:44 -0500 Message-ID: <50FE0F72.6070501@huawei.com> Date: Tue, 22 Jan 2013 12:02:58 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130107 Thunderbird/17.0.2 MIME-Version: 1.0 To: Stephane Eranian CC: Peter Zijlstra , Ingo Molnar , LKML Subject: perf: cgroup: INFO: suspicious RCU usage Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Got this warning as soon as I ran "perf stat -a -e faults -G cgrp1 -- sleep 1" This is a long-standing bug. At least I can trigger the same warning in 3.4 kernel. There were several bug reports before, but no one seems to care? =============================== [ INFO: suspicious RCU usage. ] 3.8.0-rc2-default+ #17 Not tainted ------------------------------- include/linux/cgroup.h:534 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 1 lock held by swapper/0/0: #0: (&cpuctx_lock){-.....}, at: [] perf_ctx_lock+0x15/0x30 stack backtrace: Pid: 0, comm: swapper/0 Not tainted 3.8.0-rc2-tj-0.7-default+ #17 Call Trace: [] lockdep_rcu_suspicious+0xe3/0x130 [] __perf_install_in_context+0x1a6/0x210 [] remote_function+0x49/0x60 [] ? generic_smp_call_function_single_interrupt+0x57/0x120 [] generic_smp_call_function_single_interrupt+0xc6/0x120 [] ? disable_cpuidle+0x20/0x20 [] smp_call_function_single_interrupt+0x27/0x40 [] call_function_single_interrupt+0x72/0x80 [] ? cpuidle_wrap_enter+0x53/0xa0 [] ? cpuidle_wrap_enter+0x4f/0xa0 [] cpuidle_enter_tk+0x10/0x20 [] cpuidle_enter_state+0x17/0x50 [] cpuidle_idle_call+0x13a/0x1c0 [] cpu_idle+0x9f/0xf0 [] rest_init+0xdf/0x160 [] ? csum_partial_copy_generic+0x170/0x170 [] start_kernel+0x372/0x442 [] ? repair_env_string+0x58/0x58 [] ? memblock_reserve+0x2e/0x4e [] x86_64_start_reservations+0xa5/0xc2 [] x86_64_start_kernel+0x10f/0x12a [] ? early_idt_handlers+0x120/0x120