From patchwork Thu Jun 6 16:16:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suzuki K Poulose X-Patchwork-Id: 165988 Delivered-To: patch@linaro.org Received: by 2002:a92:9e1a:0:0:0:0:0 with SMTP id q26csp8996515ili; Thu, 6 Jun 2019 09:17:05 -0700 (PDT) X-Google-Smtp-Source: APXvYqxRvSXD7sYo2KItM21ANCu2F74GIqRMxO4Qlu9Jn8MgDQuQ5MzYJ6QUN83M13aV9NSe8LKO X-Received: by 2002:aa7:9aaf:: with SMTP id x15mr1637735pfi.214.1559837825677; Thu, 06 Jun 2019 09:17:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1559837825; cv=none; d=google.com; s=arc-20160816; b=XP0cqsZX8TwpAP9sWm9xTooaxE+MDBqq3ox5RgDWTnPrUr3GPrNXDLrvVQrPPP3kxd quX5BkKmSzRxhyiqZITPtswIydZVqbprhScNztW+sFR4XikJyemMInk0ow2J8w5Oy4tj Ml8NSfdKp92NBzjSS9jBhKUl+xSZu8wGte1K3zVbn6fx4hHXyh/bjTjGRR/yteMQEk/m SQtabGQjrJqcoykPz11XKcfM6bf0+RLUNRgiL4qGK9Zgnc7GtnH+Ub3JLGbzIGsp1Z68 o/X3fw+ufiRKRv8PZtBmjr8nfIEhrtIBu9Y6xcs7bHBIG7LWIk54iyCgW2INekZ0RRAE ofBg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from; bh=bVeqE+Xn/TUTgfs/eF0peP1mlptk4SW1n9fSfnmcuFA=; b=nZSDDrsemr1k07V8jWPVoQcvgFknaeorXMjW6FpZ7Z0K44NAnTZGoljuqU53rhl+fp uhWxGvjoTtnUsObc6w9RAk2vuoKeEPKrnZUkWD1Z73Tuyv9X93EPX1ZYJ1qU4R/WAEJx ShMO3nyL+LHP3ztX93KCvJCLpMEQho0tMLOIcGsvzFmw5uy8hqK2UDer7nyBY7LzypSB U6q1TLxT/FIsI8v4J+8+XfFwiEBedb1iJorb4aHbgsdheeJTF/2El/jHGvJ0AN/bFAcG kaJxoujaS/Iv0Rd+1yFLuXlMhb24KqTgQ4qA8du5Wyue+4xDUakrX+cFhSwwjV+T5xOl P28g== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id x10si2382097pfj.93.2019.06.06.09.17.05; Thu, 06 Jun 2019 09:17:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729696AbfFFQRE (ORCPT + 30 others); Thu, 6 Jun 2019 12:17:04 -0400 Received: from foss.arm.com ([217.140.101.70]:49826 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729671AbfFFQRC (ORCPT ); Thu, 6 Jun 2019 12:17:02 -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 3AA6E15AB; Thu, 6 Jun 2019 09:17:02 -0700 (PDT) Received: from en101.cambridge.arm.com (en101.cambridge.arm.com [10.1.196.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 4E85B3F690; Thu, 6 Jun 2019 09:17:01 -0700 (PDT) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org, Suzuki K Poulose Subject: [PATCH v4 2/4] coresight: tmc-etr: alloc_perf_buf: Do not call smp_processor_id from preemptible Date: Thu, 6 Jun 2019 17:16:45 +0100 Message-Id: <1559837807-15447-3-git-send-email-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1559837807-15447-1-git-send-email-suzuki.poulose@arm.com> References: <1559837807-15447-1-git-send-email-suzuki.poulose@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org During a perf session we try to allocate buffers on the "node" associated with the CPU the event is bound to. If it is not bound to a CPU, we use the current CPU node, using smp_processor_id(). However this is unsafe in a pre-emptible context and could generate the splats as below : BUG: using smp_processor_id() in preemptible [00000000] code: perf/1743 caller is tmc_alloc_etr_buffer+0x1bc/0x1f0 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 tmc_alloc_etr_buffer+0x1bc/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 Use NUMA_NO_NODE hint instead of using the current node for events not bound to CPUs. Fixes: 22f429f19c4135d51e9 ("coresight: etm-perf: Add support for ETR backend") Cc: Mathieu Poirier Signed-off-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) -- 2.7.4 diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 7c81f63..5d2bf6d 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1184,14 +1184,11 @@ static struct etr_buf * alloc_etr_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; unsigned long size; - if (cpu == -1) - cpu = smp_processor_id(); - node = cpu_to_node(cpu); - + node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); /* * Try to match the perf ring buffer size if it is larger * than the size requested via sysfs.