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=-1.0 required=3.0 tests=MAILING_LIST_MULTI,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 7D2D3C4321D for ; Fri, 17 Aug 2018 11:46:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 433AA208EB for ; Fri, 17 Aug 2018 11:46:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 433AA208EB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727290AbeHQOtO (ORCPT ); Fri, 17 Aug 2018 10:49:14 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:45248 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726134AbeHQOtN (ORCPT ); Fri, 17 Aug 2018 10:49:13 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2B17D40241C7; Fri, 17 Aug 2018 11:46:04 +0000 (UTC) Received: from krava.brq.redhat.com (unknown [10.43.17.209]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8D6782142F21; Fri, 17 Aug 2018 11:46:02 +0000 (UTC) From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: lkml , Ingo Molnar , Namhyung Kim , David Ahern , Alexander Shishkin , Peter Zijlstra , =?UTF-8?q?Jaroslav=20=C5=A0karvada?= , Joe Mario Subject: [PATCH 2/2] perf python: Fix pyrf_evlist__read_on_cpu interface Date: Fri, 17 Aug 2018 13:45:56 +0200 Message-Id: <20180817114556.28000-3-jolsa@kernel.org> In-Reply-To: <20180817114556.28000-1-jolsa@kernel.org> References: <20180817114556.28000-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Fri, 17 Aug 2018 11:46:04 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Fri, 17 Aug 2018 11:46:04 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jolsa@kernel.org' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jaroslav reported errors from valgrind over perf python script: # echo 0 > /sys/devices/system/cpu/cpu4/online # valgrind ./test.py ==7524== Memcheck, a memory error detector ... ==7524== Command: ./test.py ==7524== pid 7526 exited ==7524== Invalid read of size 8 ==7524== at 0xCC2C2B3: perf_mmap__read_forward (evlist.c:780) ==7524== by 0xCC2A681: pyrf_evlist__read_on_cpu (python.c:959) ... ==7524== Address 0x65c4868 is 16 bytes after a block of size 459,36.. ==7524== at 0x4C2B955: calloc (vg_replace_malloc.c:711) ==7524== by 0xCC2F484: zalloc (util.h:35) ==7524== by 0xCC2F484: perf_evlist__alloc_mmap (evlist.c:978) ... The reason for this is in the python interface, that allows script to pass arbitrary cpu number, which is then used to access struct perf_evlist::mmap array. That's obviously wrong and works only when if all cpus are available and fails if some cpu is missing, like in the example above. This patch makes the pyrf_evlist__read_on_cpu search the evlist's maps array for the proper map to access. It's linear search at the moment. Based on the way how is the read_on_cpu used, I don't think we need to be fast in here. But we could add some hash in the middle to make it fast/er. We don't allow python interface to set write_backward event attribute, so it's safe to check only evlist's mmaps. Reported-by: Jaroslav Škarvada Link: http://lkml.kernel.org/n/tip-nje64txu8bcop0ogjvbt8i54@git.kernel.org Signed-off-by: Jiri Olsa --- tools/perf/util/python.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c index f74fbb652a4f..ce501ba14b08 100644 --- a/tools/perf/util/python.c +++ b/tools/perf/util/python.c @@ -11,6 +11,7 @@ #include "cpumap.h" #include "print_binary.h" #include "thread_map.h" +#include "mmap.h" #if PY_MAJOR_VERSION < 3 #define _PyUnicode_FromString(arg) \ @@ -976,6 +977,20 @@ static PyObject *pyrf_evlist__add(struct pyrf_evlist *pevlist, return Py_BuildValue("i", evlist->nr_entries); } +static struct perf_mmap *get_md(struct perf_evlist *evlist, int cpu) +{ + int i; + + for (i = 0; i < evlist->nr_mmaps; i++) { + struct perf_mmap *md = &evlist->mmap[i]; + + if (md->cpu == cpu) + return md; + } + + return NULL; +} + static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist, PyObject *args, PyObject *kwargs) { @@ -990,7 +1005,10 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist, &cpu, &sample_id_all)) return NULL; - md = &evlist->mmap[cpu]; + md = get_md(evlist, cpu); + if (!md) + return NULL; + if (perf_mmap__read_init(md) < 0) goto end; -- 2.17.1