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 X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACF28C04A6B for ; Fri, 10 May 2019 10:38:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 87E622175B for ; Fri, 10 May 2019 10:38:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727618AbfEJKib (ORCPT ); Fri, 10 May 2019 06:38:31 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:43048 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727251AbfEJKib (ORCPT ); Fri, 10 May 2019 06:38:31 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A6C88374; Fri, 10 May 2019 03:38:30 -0700 (PDT) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A42723F738; Fri, 10 May 2019 03:38:29 -0700 (PDT) Subject: Re: [PATCH 1/4] coresight: tmc-etr: Do not call smp_processor_id() from preemptible To: Suzuki K Poulose , mathieu.poirier@linaro.org Cc: coresight@lists.linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <1557480663-16759-1-git-send-email-suzuki.poulose@arm.com> <1557480663-16759-2-git-send-email-suzuki.poulose@arm.com> From: Robin Murphy Message-ID: <319d4d63-326b-9bb5-6a24-f7aa8ec549f9@arm.com> Date: Fri, 10 May 2019 11:38:28 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <1557480663-16759-2-git-send-email-suzuki.poulose@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Suzuki, On 10/05/2019 10:31, Suzuki K Poulose wrote: > Instead of using smp_processor_id() to figure out the node, > use the numa_node_id() for the current CPU node to avoid > splats like : > > BUG: using smp_processor_id() in preemptible [00000000] code: perf/1743 > caller is alloc_etr_buf.isra.6+0x80/0xa0 > CPU: 1 PID: 1743 Comm: perf Not tainted 5.1.0-rc6-147786-g116841e #344 > Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019 > Call trace: > dump_backtrace+0x0/0x150 > show_stack+0x14/0x20 > dump_stack+0x9c/0xc4 > debug_smp_processor_id+0x10c/0x110 > alloc_etr_buf.isra.6+0x80/0xa0 > tmc_alloc_etr_buffer+0x12c/0x1f0 > etm_setup_aux+0x1c4/0x230 > rb_alloc_aux+0x1b8/0x2b8 > perf_mmap+0x35c/0x478 > mmap_region+0x34c/0x4f0 > do_mmap+0x2d8/0x418 > vm_mmap_pgoff+0xd0/0xf8 > ksys_mmap_pgoff+0x88/0xf8 > __arm64_sys_mmap+0x28/0x38 > el0_svc_handler+0xd8/0x138 > el0_svc+0x8/0xc > > Fixes: 855ab61c16bf70b646 ("coresight: tmc-etr: Refactor function tmc_etr_setup_perf_buf()") > Cc: Mathieu Poirier > Signed-off-by: Suzuki K Poulose > --- > drivers/hwtracing/coresight/coresight-tmc-etr.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c > index 793639f..cae9d8a 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c > +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c > @@ -1323,13 +1323,11 @@ static struct etr_perf_buffer * > tmc_etr_setup_perf_buf(struct tmc_drvdata *drvdata, struct perf_event *event, > int nr_pages, void **pages, bool snapshot) > { > - int node, cpu = event->cpu; > + int node; > struct etr_buf *etr_buf; > struct etr_perf_buffer *etr_perf; > > - if (cpu == -1) > - cpu = smp_processor_id(); > - node = cpu_to_node(cpu); > + node = (event->cpu == -1) ? numa_node_id() : cpu_to_node(event->cpu); If cpu == -1 represents a "don't care" scenario, it might be clearer to just use NUMA_NO_NODE instead, and let the allocator handle it. Robin. > > etr_perf = kzalloc_node(sizeof(*etr_perf), GFP_KERNEL, node); > if (!etr_perf) >