Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755562AbdLVEnY (ORCPT ); Thu, 21 Dec 2017 23:43:24 -0500 Received: from ozlabs.org ([103.22.144.67]:33911 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753035AbdLVEnX (ORCPT ); Thu, 21 Dec 2017 23:43:23 -0500 X-powerpc-patch-notification: thanks X-powerpc-patch-commit: ad2b6e01024ef23bddc3ce0bcb115ecd8c520b7e In-Reply-To: <1512451838-10456-1-git-send-email-anju@linux.vnet.ibm.com> To: Anju T Sudhakar From: Michael Ellerman Cc: maddy@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, anju@linux.vnet.ibm.com, linux-kernel@vger.kernel.org Subject: Re: powerpc/perf: Fix nest-imc cpuhotplug callback failure Message-Id: <3z2wqs6MWtz9s7B@ozlabs.org> Date: Fri, 22 Dec 2017 15:43:21 +1100 (AEDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3804 Lines: 53 On Tue, 2017-12-05 at 05:30:38 UTC, Anju T Sudhakar wrote: > Call trace observed during boot: > > Faulting instruction address: 0xc000000000248340 > cpu 0x0: Vector: 380 (Data Access Out of Range) at [c000000ff66fb850] > pc: c000000000248340: event_function_call+0x50/0x1f0 > lr: c00000000024878c: perf_remove_from_context+0x3c/0x100 > sp: c000000ff66fbad0 > msr: 9000000000009033 > dar: 7d20e2a6f92d03c0 > current = 0xc000000ff6679200 > paca = 0xc00000000fd40000 softe: 0 irq_happened: 0x01 > pid = 14, comm = cpuhp/0 > Linux version 4.14.0-rc2-42789-ge8eae4b (rgrimm@XXXX) (gcc version 5.4.0 > 20160609 (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.4)) #1 SMP Thu Nov 16 14:35:14 CST > 2017 > enter ? for help > [c000000ff66fbb80] c00000000024878c perf_remove_from_context+0x3c/0x100 > [c000000ff66fbbc0] c00000000024e84c perf_pmu_migrate_context+0x10c/0x380 > [c000000ff66fbc60] c0000000000ca050 ppc_nest_imc_cpu_offline+0x1b0/0x210 > [c000000ff66fbcb0] c0000000000d5d54 cpuhp_invoke_callback+0x194/0x620 > [c000000ff66fbd20] c0000000000d702c cpuhp_thread_fun+0x7c/0x1b0 > [c000000ff66fbd60] c00000000010ad90 smpboot_thread_fn+0x290/0x2a0 > [c000000ff66fbdc0] c000000000104818 kthread+0x168/0x1b0 > [c000000ff66fbe30] c00000000000b5a0 ret_from_kernel_thread+0x5c/0xbc > > While registering the cpuhotplug callbacks for nest-imc, if we fail in the > cpuhotplug online path for any random node in a multi node system (because > the opal call to stop nest-imc counters fails for that node), > ppc_nest_imc_cpu_offline() will get invoked for other nodes who successfully > returned from cpuhotplug online path. > > This call trace is generated since in the ppc_nest_imc_cpu_offline() > path we are trying to migrate the event context, when nest-imc counters are > not even initialized. > > Patch to add a check to ensure that nest-imc is registered before migrating > the event context. > > Note: > Madhavan Srinivasan has recently send a skiboot patch to have a check in the > skiboot code to make sure that the microcode is initialized in all the chips, > before enabling the nest units. > https://patchwork.ozlabs.org/patch/844047/ (v2) > > Signed-off-by: Anju T Sudhakar > Reviewed-by: Madhavan Srinivasan Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/ad2b6e01024ef23bddc3ce0bcb115e cheers