Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752340AbbKCKGt (ORCPT ); Tue, 3 Nov 2015 05:06:49 -0500 Received: from ozlabs.org ([103.22.144.67]:50573 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750900AbbKCKGq (ORCPT ); Tue, 3 Nov 2015 05:06:46 -0500 Message-ID: <1446545202.2801.2.camel@ellerman.id.au> Subject: Re: [PATCH] powerpc: tracing: don't trace hcalls on offline CPUs From: Michael Ellerman To: Denis Kirjanov , linuxppc-dev@ozlabs.org Cc: "Paul E. McKenney" , Anton Blanchard , Steven Rostedt , linux-kernel@vger.kernel.org Date: Tue, 03 Nov 2015 21:06:42 +1100 In-Reply-To: <1446145810-5383-1-git-send-email-kda@linux-powerpc.org> References: <1446145810-5383-1-git-send-email-kda@linux-powerpc.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.5-1ubuntu3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2139 Lines: 39 On Thu, 2015-10-29 at 22:10 +0300, Denis Kirjanov wrote: > ./drmgr -c cpu -a -r gives the following warning: > > [ 2327.035563] RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 1 > [ 2327.035564] no locks held by swapper/12/0. > [ 2327.035565] stack backtrace: > [ 2327.035567] CPU: 12 PID: 0 Comm: swapper/12 Tainted: G S 4.3.0-rc3-00060-g353169a #5 > [ 2327.035568] Call Trace: > [ 2327.035573] [c0000001d62578e0] [c0000000008977fc] .dump_stack+0x98/0xd4 (unreliable) > [ 2327.035577] [c0000001d6257960] [c000000000109bd8] .lockdep_rcu_suspicious+0x108/0x170 > [ 2327.035580] [c0000001d62579f0] [c00000000006a1d0] .__trace_hcall_exit+0x2b0/0x2c0 > [ 2327.035584] [c0000001d6257ab0] [c00000000006a2e8] plpar_hcall_norets_trace+0x70/0x8c > [ 2327.035588] [c0000001d6257b20] [c000000000067a14] .icp_hv_set_cpu_priority+0x54/0xc0 > [ 2327.035592] [c0000001d6257ba0] [c000000000066c5c] .xics_teardown_cpu+0x5c/0xa0 > [ 2327.035595] [c0000001d6257c20] [c0000000000747ac] .pseries_mach_cpu_die+0x6c/0x320 > [ 2327.035598] [c0000001d6257cd0] [c0000000000439cc] .cpu_die+0x3c/0x60 > [ 2327.035602] [c0000001d6257d40] [c0000000000183d8] .arch_cpu_idle_dead+0x28/0x40 > [ 2327.035606] [c0000001d6257db0] [c0000000000ff1dc] .cpu_startup_entry+0x4fc/0x560 > [ 2327.035610] [c0000001d6257ed0] [c000000000043728] .start_secondary+0x328/0x360 > [ 2327.035614] [c0000001d6257f90] [c000000000008a6c] start_secondary_prolog+0x10/0x14 > [ 2327.035620] cpu 12 (hwid 12) Ready to die... > [ 2327.144463] cpu 13 (hwid 13) Ready to die... > [ 2327.294180] cpu 14 (hwid 14) Ready to die... > [ 2327.403599] cpu 15 (hwid 15) Ready to die... > > Make the hypervisor tracepoints conditional by introducing > TRACE_EVENT_FN_COND similar to TRACE_EVENT_FN We've fixed other cases like this with RCU_NONIDLE(), but I assume that doesn't work here because we're actually offline? cheers -- 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/