Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755912Ab3EVK25 (ORCPT ); Wed, 22 May 2013 06:28:57 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:35743 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754079Ab3EVK2z (ORCPT ); Wed, 22 May 2013 06:28:55 -0400 Date: Wed, 22 May 2013 02:51:29 -0700 From: "Paul E. McKenney" To: Dave Jones , Linux Kernel , fweisbec@gmail.com Subject: Re: WARNING: at kernel/rcutree.c:388 rcu_eqs_enter Message-ID: <20130522095129.GA3578@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130521173100.GA2076@redhat.com> <20130521235813.GA18737@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130521235813.GA18737@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13052210-5406-0000-0000-000008B7A8B3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4131 Lines: 83 On Tue, May 21, 2013 at 07:58:13PM -0400, Dave Jones wrote: > On Tue, May 21, 2013 at 01:31:00PM -0400, Dave Jones wrote: > > I'm also seeing this quite often.. > > [ 576.156848] WARNING: at kernel/rcutree.c:388 rcu_eqs_enter+0x9b/0xb0() > [ 576.165962] Modules linked in: snd_seq_dummy tun fuse bnep hidp can_raw phonet rfcomm rose bluetooth netrom af_rxrpc scsi_transport_iscsi caif_socket caif ipt_ULOG af_key pppoe pppox af_802154 ppp_generic nfnetlink slhc llc2 can_bcm can irda atm ax25 ipx rds p8023 p8022 crc_ccitt x25 nfc rfkill decnet appletalk psnap llc snd_hda_codec_realtek snd_hda_codec_hdmi xfs libcrc32c microcode snd_hda_intel snd_hda_codec pcspkr i915 snd_hwdep snd_seq snd_seq_device e1000e snd_pcm i2c_algo_bit drm_kms_helper drm ptp snd_page_alloc snd_timer pps_core snd i2c_core soundcore video > [ 576.235012] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.0-rc2+ #2 > [ 576.264999] ffffffff819e8d1d ffffffff81c01e90 ffffffff816599f1 ffffffff81c01ec8 > [ 576.265002] ffffffff8104a171 ffff8802449cdb60 0000000000000000 0000000000000000 > [ 576.265005] ffffffff81c01fd8 ffffffff81c01fd8 ffffffff81c01ed8 ffffffff8104a24a > [ 576.265006] Call Trace: > [ 576.265011] [] dump_stack+0x19/0x1b > [ 576.265015] [] warn_slowpath_common+0x61/0x80 > [ 576.265018] [] warn_slowpath_null+0x1a/0x20 > [ 576.265022] [] rcu_eqs_enter+0x9b/0xb0 > [ 576.265025] [] rcu_idle_enter+0x19/0x40 > [ 576.265029] [] cpu_startup_entry+0x92/0x420 > [ 576.265034] [] rest_init+0x137/0x140 > [ 576.265037] [] ? rest_init+0x5/0x140 > [ 576.265041] [] start_kernel+0x3ec/0x3f9 > [ 576.265044] [] ? repair_env_string+0x5c/0x5c > [ 576.265048] [] x86_64_start_reservations+0x2a/0x2c > [ 576.265050] [] x86_64_start_kernel+0xcc/0xcf > [ 576.265052] ---[ end trace d18cda23dfca05cc ]--- > > WARN_ON_ONCE((oldval & DYNTICK_TASK_NEST_MASK) == 0); Hmmm... Could you please try the patch below? Untested, probably does not even compile. [ . . . ] > I'm trying to collect all the WARN's in rcutree. 5/29 isn't a bad start :) ;-) ;-) ;-) Just to make your testing more exiting... I will be getting on a plane in a few hours, and will be on planes and in airports for about 30 hours. I will check in as connectivity permits. Thanx, Paul ------------------------------------------------------------------------ trace: Allow idle-safe tracepoints to be called from irq __DECLARE_TRACE_RCU() currently creates an _rcuidle() tracepoint which may safely be invoked from what RCU considers to be an idle CPU. However, these _rcuidle() tracepoints may -not- be invoked from the handler of an irq taken from idle, because rcu_idle_enter() zeroes RCU's nesting-level counter, so that the rcu_irq_exit() returning to idle will trigger a WARN_ON_ONCE(). This commit therefore substitutes rcu_irq_enter() for rcu_idle_exit() and rcu_irq_exit() for rcu_idle_enter() in order to make the _rcuidle() tracepoints usable from irq handlers as well as from process context. Reported-by: Dave Jones Signed-off-by: Paul E. McKenney Cc: Steven Rostedt diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 2f322c3..f8e084d 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -145,8 +145,8 @@ static inline void tracepoint_synchronize_unregister(void) TP_PROTO(data_proto), \ TP_ARGS(data_args), \ TP_CONDITION(cond), \ - rcu_idle_exit(), \ - rcu_idle_enter()); \ + rcu_irq_enter(), \ + rcu_irq_exit()); \ } #else #define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) -- 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/