From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4BAC8C4332F for ; Thu, 15 Dec 2022 15:02:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229514AbiLOPCs (ORCPT ); Thu, 15 Dec 2022 10:02:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbiLOPCr (ORCPT ); Thu, 15 Dec 2022 10:02:47 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31322C76D; Thu, 15 Dec 2022 07:02:46 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B78C7B81BAD; Thu, 15 Dec 2022 15:02:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5B57C433D2; Thu, 15 Dec 2022 15:02:42 +0000 (UTC) Date: Thu, 15 Dec 2022 10:02:41 -0500 From: Steven Rostedt To: "Paul E. McKenney" Cc: Masami Hiramatsu , LKML , Linux Trace Kernel , Andrew Morton , Mathieu Desnoyers Subject: Re: [PATCH] tracing: Do not synchronize freeing of trigger filter on boot up Message-ID: <20221215100241.73a30da8@gandalf.local.home> In-Reply-To: <20221214200333.GA3208104@paulmck-ThinkPad-P17-Gen-1> References: <20221213172429.7774f4ba@gandalf.local.home> <20221214084954.e759647a2f5f1a38bc78b371@kernel.org> <20221214200333.GA3208104@paulmck-ThinkPad-P17-Gen-1> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Wed, 14 Dec 2022 12:03:33 -0800 "Paul E. McKenney" wrote: > > > Avoid calling the synchronization function when system_state is > > > SYSTEM_BOOTING. > > > > Shouldn't this be done inside tracepoint_synchronize_unregister()? > > Then, it will prevent similar warnings if we expand boot time feature. > > How about the following wide-spectrum fix within RCU_LOCKDEP_WARN()? > Just in case there are ever additional issues of this sort? Adding more tracing command line parameters is triggering this more. I now hit: [ 0.213442] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies. [ 0.214653] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=8 [ 0.232023] ------------[ cut here ]------------ [ 0.232704] WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:1410 rcu_poll_gp_seq_start_unlocked+0x8a/0xa0 [ 0.234241] Modules linked in: [ 0.234715] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.0-rc6-test-00046-ga0ca17bfe724-dirty #63 [ 0.236069] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-debian-1.16.0-4 04/01/2014 [ 0.237549] RIP: 0010:rcu_poll_gp_seq_start_unlocked+0x8a/0xa0 [ 0.238495] Code: 02 0f 0b 48 89 ee 5b 48 c7 c7 00 ca b1 b3 5d e9 cc 0f c1 00 65 8b 05 85 f3 dd 4d 85 c0 75 a1 65 8b 05 d6 f0 dd 4d 85 c0 75 96 <0f> 0b eb 92 5b 5d e9 eb 18 fc 00 66 66 2e 0f 1f 84 00 00 00 00 00 [ 0.241433] RSP: 0000:ffffffffb3a03d28 EFLAGS: 00010046 [ 0.242289] RAX: 0000000000000000 RBX: ffffffffb3bcfc48 RCX: 0000000000000001 [ 0.243355] RDX: 0000000080000001 RSI: 0000000000000001 RDI: ffffffffb3bcfc48 [ 0.244421] RBP: 0000000000000000 R08: ffff97a3c012b8f8 R09: fffffffffffffffe [ 0.245569] R10: ffffffffb3a03e78 R11: 00000000ffffffff R12: 0000000000000040 [ 0.246752] R13: ffffffffb3a30500 R14: ffffffffb3be6180 R15: ffff97a3c0355d10 [ 0.247826] FS: 0000000000000000(0000) GS:ffff97a537c00000(0000) knlGS:0000000000000000 [ 0.249084] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.250012] CR2: ffff97a51e201000 CR3: 000000025c826001 CR4: 00000000000606b0 [ 0.251122] Call Trace: [ 0.251491] [ 0.251810] synchronize_rcu+0xb6/0x1e0 [ 0.252393] ? smp_call_function_many_cond+0x36d/0x3b0 [ 0.253243] ? enable_trace_buffered_event+0x10/0x10 [ 0.254021] trace_buffered_event_disable+0x7c/0x140 [ 0.254786] __ftrace_event_enable_disable+0x11c/0x250 [ 0.255559] __ftrace_set_clr_event_nolock+0xe3/0x130 [ 0.256321] ftrace_set_clr_event+0x9a/0xe0 [ 0.256976] early_enable_events+0x64/0xa8 [ 0.257647] trace_event_init+0xd6/0x2dd [ 0.258305] start_kernel+0x760/0x9e0 [ 0.258862] secondary_startup_64_no_verify+0xe5/0xeb [ 0.259634] [ 0.259966] irq event stamp: 0 [ 0.260427] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 0.261448] hardirqs last disabled at (0): [<0000000000000000>] 0x0 [ 0.262424] softirqs last enabled at (0): [<0000000000000000>] 0x0 [ 0.263402] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 0.264345] ---[ end trace 0000000000000000 ]--- [ 0.265088] ------------[ cut here ]------------ Where kernel/rcu/tree.c:1410 is at: // Make the polled API aware of the beginning of a grace period, but // where caller does not hold the root rcu_node structure's lock. static void rcu_poll_gp_seq_start_unlocked(unsigned long *snap) { unsigned long flags; struct rcu_node *rnp = rcu_get_root(); if (rcu_init_invoked()) { lockdep_assert_irqs_enabled(); <<-------------- 1410 raw_spin_lock_irqsave_rcu_node(rnp, flags); } rcu_poll_gp_seq_start(snap); if (rcu_init_invoked()) raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } -- Steve