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=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, USER_AGENT_GIT 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 AF3E7C4321D for ; Mon, 20 Aug 2018 16:17:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6BCA52172F for ; Mon, 20 Aug 2018 16:17:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="OCMkWnQW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6BCA52172F 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 S1727990AbeHTTdd (ORCPT ); Mon, 20 Aug 2018 15:33:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:35930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726024AbeHTTdc (ORCPT ); Mon, 20 Aug 2018 15:33:32 -0400 Received: from jouet.infradead.org (unknown [179.97.41.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1CBB621731; Mon, 20 Aug 2018 16:17:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1534781836; bh=x1YPTy1u63V3eDEkNPvURYUs5E1nZWyKq8T0BSzfMl4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OCMkWnQW0zSfCwAVSc9cjhQTus9VzmJltcZAzc/BX0w2FnYbClM1E0lBdOTWH8TCE CylR786NZRt5fwRtD5NVJ29LteS/vG8x3J1J7EW/3AxBxnmuUOujWirgi7xeq/dlvb dFy2CpjU2HwFkg/CmbBmMj1JgUMoPMD4k/v5iaIA= From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Jiri Olsa , Alexander Shishkin , David Ahern , Joe Mario , Namhyung Kim , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH 19/21] perf python: Fix pyrf_evlist__read_on_cpu() interface Date: Mon, 20 Aug 2018 13:16:00 -0300 Message-Id: <20180820161602.6830-20-acme@kernel.org> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180820161602.6830-1-acme@kernel.org> References: <20180820161602.6830-1-acme@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Olsa 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 a 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 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 Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: David Ahern Cc: Joe Mario Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20180817114556.28000-3-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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; -- 2.14.4