Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754590AbbKCM6v (ORCPT ); Tue, 3 Nov 2015 07:58:51 -0500 Received: from mail-yk0-f180.google.com ([209.85.160.180]:33422 "EHLO mail-yk0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753709AbbKCM6p (ORCPT ); Tue, 3 Nov 2015 07:58:45 -0500 MIME-Version: 1.0 X-Originating-IP: [195.54.192.103] In-Reply-To: <1446545202.2801.2.camel@ellerman.id.au> References: <1446145810-5383-1-git-send-email-kda@linux-powerpc.org> <1446545202.2801.2.camel@ellerman.id.au> Date: Tue, 3 Nov 2015 15:58:44 +0300 Message-ID: Subject: Re: [PATCH] powerpc: tracing: don't trace hcalls on offline CPUs From: Denis Kirjanov To: Michael Ellerman Cc: linuxppc-dev@ozlabs.org, "Paul E. McKenney" , Anton Blanchard , Steven Rostedt , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2347 Lines: 57 On 11/3/15, Michael Ellerman wrote: > 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? Yes, in this case we're moving the complete core offline through dlpar... > > 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/