From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751236AbcBMSZ4 (ORCPT ); Sat, 13 Feb 2016 13:25:56 -0500 Received: from mail-lb0-f193.google.com ([209.85.217.193]:34854 "EHLO mail-lb0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751189AbcBMSZp (ORCPT ); Sat, 13 Feb 2016 13:25:45 -0500 From: Denis Kirjanov To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com, Denis Kirjanov Subject: [PATCH 2/2] tracing/rcu: don't trace rcu_callback on offline CPUs Date: Sat, 13 Feb 2016 21:22:53 +0300 Message-Id: <1455387773-4245-2-git-send-email-kda@linux-powerpc.org> X-Mailer: git-send-email 2.4.0 In-Reply-To: <1455387773-4245-1-git-send-email-kda@linux-powerpc.org> References: <1455387773-4245-1-git-send-email-kda@linux-powerpc.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tracepoints use RCU for protection and they must not be called on offline CPUS. So make this tracepoint conditional. INFO: suspicious RCU usage. ] [ 413.344670] 4.4.0-00006-g0fe53e8-dirty #33 Tainted: G S [ 413.344672] ------------------------------- [ 413.344673] include/trace/events/rcu.h:457 suspicious rcu_dereference_check() usage! [ 413.344674] other info that might help us debug this: [ 413.344676] RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 1 [ 413.344678] no locks held by swapper/4/0. [ 413.344679] stack backtrace: [ 413.344682] CPU: 4 PID: 0 Comm: swapper/4 Tainted: G S 4.4.0-00006-g0fe53e8-dirty #33 [ 413.344683] Call Trace: [ 413.344692] [c0000005b76b7800] [c0000000008bb080] .dump_stack+0x98/0xd4 (unreliable) [ 413.344698] [c0000005b76b7880] [c00000000010c8b8] .lockdep_rcu_suspicious+0x108/0x170 [ 413.344703] [c0000005b76b7910] [c00000000013b9e4] .__call_rcu.constprop.60+0x264/0x600 [ 413.344708] [c0000005b76b79e0] [c0000000002bceec] .put_object+0x5c/0x80 [ 413.344712] [c0000005b76b7a60] [c00000000029a368] .kmem_cache_free+0x298/0x450 [ 413.344716] [c0000005b76b7b00] [c000000000093494] .__mmdrop+0x54/0x150 [ 413.344720] [c0000005b76b7b90] [c0000000000e4010] .idle_task_exit+0x130/0x140 [ 413.344725] [c0000005b76b7c20] [c000000000075804] .pseries_mach_cpu_die+0x64/0x310 [ 413.344730] [c0000005b76b7cd0] [c000000000043e7c] .cpu_die+0x3c/0x60 [ 413.344734] [c0000005b76b7d40] [c0000000000188d8] .arch_cpu_idle_dead+0x28/0x40 [ 413.344738] [c0000005b76b7db0] [c000000000101e8c] .cpu_startup_entry+0x50c/0x560 [ 413.344741] [c0000005b76b7ed0] [c000000000043bd8] .start_secondary+0x328/0x360 [ 413.344746] [c0000005b76b7f90] [c000000000008a6c] start_secondary_prolog+0x10/0x14 Signed-off-by: Denis Kirjanov --- include/trace/events/rcu.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index ef72c4a..5470f2f 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -435,6 +435,8 @@ TRACE_EVENT(rcu_callback, TP_ARGS(rcuname, rhp, qlen_lazy, qlen), + TP_CONDITION(cpu_online(raw_smp_processor_id())), + TP_STRUCT__entry( __field(const char *, rcuname) __field(void *, rhp) -- 2.4.0