Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932608Ab2ENWZ4 (ORCPT ); Mon, 14 May 2012 18:25:56 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:58823 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932541Ab2ENWZy (ORCPT ); Mon, 14 May 2012 18:25:54 -0400 Message-ID: <4FB1866E.9000604@gmail.com> Date: Mon, 14 May 2012 16:25:50 -0600 From: David Ahern User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Peter Zijlstra CC: Linus Torvalds , Ingo Molnar , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org Subject: Re: Perf events warning.. References: <1337034048.27020.137.camel@laptop> In-Reply-To: <1337034048.27020.137.camel@laptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4044 Lines: 81 On 5/14/12 4:20 PM, Peter Zijlstra wrote: > On Fri, 2012-05-11 at 08:43 -0700, Linus Torvalds wrote: >> Peter, Ingo, Arnaldo, >> google doesn't find a warning like this, so it can't be *too* >> commonly reported. >> >> Anyway, doing some profiling of git "make test" (wonderful load for >> doing lots of small processes that do lots of page faults etc), this >> WARN_ON_ONCE() triggered: >> >> ------------[ cut here ]------------ >> WARNING: at kernel/events/core.c:2066 task_ctx_sched_out+0x63/0x70() >> Hardware name: System Product Name >> Pid: 18120, comm: git Not tainted 3.4.0-rc6-00089-g4a01c681d58f-dirty #3 >> Call Trace: >> [] warn_slowpath_common+0x75/0xb0 >> [] warn_slowpath_null+0x15/0x20 >> [] task_ctx_sched_out+0x63/0x70 >> [] perf_event_comm+0x1d6/0x2e0 >> [] ? get_random_int+0x88/0xb0 >> [] ? __mmdrop+0x62/0x90 >> [] set_task_comm+0x63/0x80 >> [] setup_new_exec+0x86/0x250 >> [] load_elf_binary+0x389/0x1930 >> [] ? load_misc_binary+0x292/0x390 >> [] ? get_user_pages+0x4d/0x50 >> [] ? get_arg_page+0xa2/0xd0 >> [] search_binary_handler+0xd5/0x200 >> [] ? elf_map+0x170/0x170 >> [] do_execve_common.clone.39+0x37d/0x430 >> [] do_execve+0x16/0x20 >> [] sys_execve+0x45/0x70 >> [] stub_execve+0x6c/0xc0 >> ---[ end trace 6fccf3db70f1b560 ]--- >> >> any comments/ideas? > > So far I can't make any of the things I came up stick. You ran something > simple like: 'perf record -e cycles:pp -F 20000 make test' ? Or did you > do something more interesting? By chance I just hit this: [ 31.528795] WARNING: at /mnt/sw/kernel-2.6.git/arch/x86/kernel/cpu/perf_event.c:1054 x86_pmu_start+0xdc/0x110() [ 31.528799] Hardware name: Bochs [ 31.528801] Modules linked in: nfs fscache auth_rpcgss nfs_acl lockd ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 nf_conntrack_ipv4 nf_defrag_ipv4 xt_state ip6table_filter nf_conntrack ip6_tables virtio_net ppdev i2c_piix4 parport_pc parport i2c_core sunrpc virtio_blk [last unloaded: scsi_wait_scan] [ 31.528825] Pid: 959, comm: find Not tainted 3.4.0-rc6+ #1 [ 31.528827] Call Trace: [ 31.528835] [] warn_slowpath_common+0x7f/0xc0 [ 31.528839] [] warn_slowpath_null+0x1a/0x20 [ 31.528843] [] x86_pmu_start+0xdc/0x110 [ 31.528847] [] x86_pmu_enable+0x212/0x270 [ 31.528854] [] perf_event_context_sched_in+0xe6/0x100 [ 31.528857] [] perf_event_comm+0x103/0x2b0 [ 31.528863] [] set_task_comm+0x72/0xe0 [ 31.528867] [] setup_new_exec+0x8b/0x240 [ 31.528873] [] load_elf_binary+0x3e7/0x19a0 [ 31.528879] [] ? get_user_pages+0x52/0x60 [ 31.528883] [] ? get_user_arg_ptr+0x38/0x80 [ 31.528887] [] search_binary_handler+0xee/0x340 [ 31.528891] [] ? load_elf_library+0x230/0x230 [ 31.528895] [] do_execve_common+0x36f/0x410 [ 31.528899] [] do_execve+0x3a/0x40 [ 31.528903] [] sys_execve+0x47/0x70 [ 31.528908] [] stub_execve+0x6c/0xc0 [ 31.528911] ---[ end trace ba6387065a9b9696 ]--- As for the something interesting part - not really: debugging the regression on 'perf stat --group -- find /usr >/dev/null' David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/