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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 49D7AC76186 for ; Wed, 24 Jul 2019 22:50:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 209392189F for ; Wed, 24 Jul 2019 22:50:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="pd8KMi+0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729606AbfGXWuH (ORCPT ); Wed, 24 Jul 2019 18:50:07 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:48270 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729595AbfGXWuE (ORCPT ); Wed, 24 Jul 2019 18:50:04 -0400 Received: by mail-qt1-f201.google.com with SMTP id x7so42839385qtp.15 for ; Wed, 24 Jul 2019 15:50:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=NxY1kodMJBd2/ei1bMYZJ0+xBcLCSsSTWKWnJLyiC4A=; b=pd8KMi+0zEXQfuPRHUcE9sM5o0zzd8ue5+jsXpSqx6c/66eG0WAG3ATGyB+CNnP0dl 5o2U6KvUPKQfe6sTG/9En17b61ENuw/XRZcBFw2/jmuv9E3Rw6u7oqlIXTyCajhjbfTH Cw6RovJEGZ4qjCs8Arl9r5NUIr3pkuykNI6xBFtxP5sXYn+t8AdXumnIMULFuurrbIYy heZCb8n/ypmJjlEKL1WOqCXqrkuCN1Tl8pvwIbwrx2gyQUNLarF+b9jzMURXCu7Sixw3 q2uIWT2wdJU6rZRPSyqI/PP7cfbAUWMXA/gOaHZlti5QnsnSjBmZtRlznNS2BoViRO4f EWyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=NxY1kodMJBd2/ei1bMYZJ0+xBcLCSsSTWKWnJLyiC4A=; b=d9MKdv5khuCkV422JczRu4TVEVJ5goMj7P1HrXEDneQlLBE05UnZQ5jobkb3XtCAs2 m7UcVcyZnZwDvmgUmI0Mb6EZF0VLoyoZHp+D/+9OBIef62bfrMNnQQ0XfD6JFKAXOFwC A/QlXAPcz9jGQ2SYUCet9NdMt493gYHeOBMvdci6mV32ETRAFMVJyaunMczMk1CXgprO reZfqEWnQ+jD//T8DwQ1pW0CjT+gz0ubgPBPhYn6D1z8kB26Z9KwWt2O8F7HZ2Lo0No2 gVoQT9B87ON0ikD/wvaCxjRo2kGSpA2W6ZBJsQzF3lrh7HF+bYYbf+KeCkhvWEBLxXkf FiJw== X-Gm-Message-State: APjAAAU6VxQAlhjYNPAexDDB82fN7qrVhsEzv7RGlpYPsa/Qq69g2Cwk 3JlyC8BAAEpaf8WMCPDyh7vufOa8 X-Google-Smtp-Source: APXvYqwTiaEmHGfxNqrCbrjI1j9LA5A9ou08lYvHVjTv1cgZyCF3303x39esyOIccerHbqj8VFBg5Cxk X-Received: by 2002:a05:620a:1f4:: with SMTP id x20mr57368093qkn.415.1564008603064; Wed, 24 Jul 2019 15:50:03 -0700 (PDT) Date: Wed, 24 Jul 2019 15:49:54 -0700 In-Reply-To: <20190724224954.229540-1-nums@google.com> Message-Id: <20190724224954.229540-3-nums@google.com> Mime-Version: 1.0 References: <20190724224954.229540-1-nums@google.com> X-Mailer: git-send-email 2.22.0.657.g960e92d24f-goog Subject: [RFC][PATCH 2/2] Fix evsel.c misaligned address errors From: Numfor Mbiziwo-Tiapo To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, songliubraving@fb.com, mbd@fb.com Cc: linux-kernel@vger.kernel.org, irogers@google.com, eranian@google.com, Numfor Mbiziwo-Tiapo Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ubsan (undefined behavior sanitizer) build of perf throws misaligned address erros during 'Sample parsing function' in perf test. To reproduce, run: make -C tools/perf USE_CLANG=1 EXTRA_CFLAGS="-fsanitize=undefined" (see the cover letter for why perf may not build) then run: tools/perf/perf test 26 -v Most of the misaligned address errors come from improperly assigning values to the u64 array in the 'perf_event__synthesize_sample' function. These are easily fixed by changing the assignments to use memcpy instead. In the 'perf_evsel__parse_sample' function, the 'u64* array' variable has varying numbers of bytes added to it depending on which if statements it passes. Since this function is called multiple times under different conditions, the 'array' variable is sometimes misaligned by 4 bytes and sometimes not. This causes issues when 'data->branch_stack' is later assigned to an element in the array. In the case that the array is misaligned we can add 4 bytes to the array to realign it. This still causes an incorrect perf data file (so the test still fails with the ubsan build) but it at least gets rid of the error. Comments? Not-Quite-Signed-off-by: Numfor Mbiziwo-Tiapo --- tools/perf/util/evsel.c | 28 ++++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index dbc0466db368..a1289fcbbb2d 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -2288,6 +2288,11 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event, sizeof(struct branch_entry); OVERFLOW_CHECK_u64(array); + if ((((u64)array) & 7) != 0) + array = (void *)array + sizeof(u32); + + assert((((u64)array) & 7) == 0); + data->branch_stack = (struct branch_stack *)array++; if (data->branch_stack->nr > max_branch_nr) @@ -2646,7 +2651,8 @@ int perf_event__synthesize_sample(union perf_event *event, u64 type, if (type & PERF_SAMPLE_REGS_USER) { if (sample->user_regs.abi) { - *array++ = sample->user_regs.abi; + memcpy(array++, &sample->user_regs.abi, + sizeof(sample->user_regs.abi)); sz = hweight_long(sample->user_regs.mask) * sizeof(u64); memcpy(array, sample->user_regs.regs, sz); array = (void *)array + sz; @@ -2657,32 +2663,31 @@ int perf_event__synthesize_sample(union perf_event *event, u64 type, if (type & PERF_SAMPLE_STACK_USER) { sz = sample->user_stack.size; - *array++ = sz; + memcpy(array++, &sz, sizeof(sample->user_stack.size)); if (sz) { memcpy(array, sample->user_stack.data, sz); array = (void *)array + sz; - *array++ = sz; + memcpy(array++, &sz, sizeof(sz)); } } if (type & PERF_SAMPLE_WEIGHT) { - *array = sample->weight; - array++; + memcpy(array++, &sample->weight, sizeof(sample->weight)); } if (type & PERF_SAMPLE_DATA_SRC) { - *array = sample->data_src; - array++; + memcpy(array++, &sample->data_src, sizeof(sample->data_src)); } if (type & PERF_SAMPLE_TRANSACTION) { - *array = sample->transaction; - array++; + memcpy(array++, &sample->transaction, + sizeof(sample->transaction)); } if (type & PERF_SAMPLE_REGS_INTR) { if (sample->intr_regs.abi) { - *array++ = sample->intr_regs.abi; + memcpy(array++, &sample->intr_regs.abi, + sizeof(sample->intr_regs.abi)); sz = hweight_long(sample->intr_regs.mask) * sizeof(u64); memcpy(array, sample->intr_regs.regs, sz); array = (void *)array + sz; @@ -2692,8 +2697,7 @@ int perf_event__synthesize_sample(union perf_event *event, u64 type, } if (type & PERF_SAMPLE_PHYS_ADDR) { - *array = sample->phys_addr; - array++; + memcpy(array++, &sample->phys_addr, sizeof(sample->phys_addr)); } return 0; -- 2.22.0.657.g960e92d24f-goog