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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 E6EA2C432C0 for ; Mon, 18 Nov 2019 14:21:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C49DB20659 for ; Mon, 18 Nov 2019 14:21:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727262AbfKROVI (ORCPT ); Mon, 18 Nov 2019 09:21:08 -0500 Received: from mga06.intel.com ([134.134.136.31]:37678 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726761AbfKROVI (ORCPT ); Mon, 18 Nov 2019 09:21:08 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Nov 2019 06:21:07 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,320,1569308400"; d="scan'208";a="208864284" Received: from linux.intel.com ([10.54.29.200]) by orsmga003.jf.intel.com with ESMTP; 18 Nov 2019 06:21:07 -0800 Received: from [10.252.10.190] (abudanko-mobl.ccr.corp.intel.com [10.252.10.190]) by linux.intel.com (Postfix) with ESMTP id 2AF935800FE; Mon, 18 Nov 2019 06:21:04 -0800 (PST) From: Alexey Budankov Subject: [PATCH v3] perf session: fix decompression of PERF_RECORD_COMPRESSED records Organization: Intel Corp. To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Ingo Molnar , Andi Kleen , linux-kernel Message-ID: Date: Mon, 18 Nov 2019 17:21:03 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Avoid termination of trace loading in case the last record in the decompressed buffer partly resides in the following mmaped PERF_RECORD_COMPRESSED record. In this case NULL value returned by fetch_mmaped_event() means to proceed to the next mmaped record then decompress it and load compressed events. The issue can be reproduced like this: $ perf record -z -- some_long_running_workload $ perf report --stdio -vv decomp (B): 44519 to 163000 decomp (B): 48119 to 174800 decomp (B): 65527 to 131072 fetch_mmaped_event: head=0x1ffe0 event->header_size=0x28, mmap_size=0x20000: fuzzed perf.data? Error: failed to process sample ... Testing: 71: Zstd perf.data compression/decompression : Ok $ tools/perf/perf report -vv --stdio decomp (B): 59593 to 262160 decomp (B): 4438 to 16512 decomp (B): 285 to 880 Looking at the vmlinux_path (8 entries long) Using vmlinux for symbols decomp (B): 57474 to 261248 prefetch_event: head=0x3fc78 event->header_size=0x28, mmap_size=0x3fc80: fuzzed or compressed perf.data? decomp (B): 25 to 32 decomp (B): 52 to 120 ... Fixes: 57fc032ad643 ("perf session: Avoid infinite loop when seeing invalid header.size") Link: https://marc.info/?l=linux-kernel&m=156580812427554&w=2 Co-developed-by: Jiri Olsa Signed-off-by: Alexey Budankov --- Changes in v3: - extended debug message with 'fuzzed or compressed perf.data?' Changes in v2: - avoided static declaration of prefetch_event(); - renamed 'ret' to 'error' for returning in case of split compressed or overlapping records; - passed only needs_swap quality into fetch_*_event() instead of the whole session object; --- tools/perf/util/session.c | 44 ++++++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 17 deletions(-) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index f07b8ecb91bc..8454a650146b 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1958,8 +1958,8 @@ static int __perf_session__process_pipe_events(struct perf_session *session) } static union perf_event * -fetch_mmaped_event(struct perf_session *session, - u64 head, size_t mmap_size, char *buf) +prefetch_event(char *buf, u64 head, size_t mmap_size, + bool needs_swap, union perf_event *error) { union perf_event *event; @@ -1971,20 +1971,32 @@ fetch_mmaped_event(struct perf_session *session, return NULL; event = (union perf_event *)(buf + head); + if (needs_swap) + perf_event_header__bswap(&event->header); - if (session->header.needs_swap) + if (head + event->header.size <= mmap_size) + return event; + + /* We're not fetching the event so swap back again */ + if (needs_swap) perf_event_header__bswap(&event->header); - if (head + event->header.size > mmap_size) { - /* We're not fetching the event so swap back again */ - if (session->header.needs_swap) - perf_event_header__bswap(&event->header); - pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx: fuzzed perf.data?\n", - __func__, head, event->header.size, mmap_size); - return ERR_PTR(-EINVAL); - } + pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx:" + " fuzzed or compressed perf.data?\n",__func__, head, event->header.size, mmap_size); - return event; + return error; +} + +static union perf_event * +fetch_mmaped_event(u64 head, size_t mmap_size, char *buf, bool needs_swap) +{ + return prefetch_event(buf, head, mmap_size, needs_swap, ERR_PTR(-EINVAL)); +} + +static union perf_event * +fetch_decomp_event(u64 head, size_t mmap_size, char *buf, bool needs_swap) +{ + return prefetch_event(buf, head, mmap_size, needs_swap, NULL); } static int __perf_session__process_decomp_events(struct perf_session *session) @@ -1997,10 +2009,8 @@ static int __perf_session__process_decomp_events(struct perf_session *session) return 0; while (decomp->head < decomp->size && !session_done()) { - union perf_event *event = fetch_mmaped_event(session, decomp->head, decomp->size, decomp->data); - - if (IS_ERR(event)) - return PTR_ERR(event); + union perf_event *event = fetch_decomp_event(decomp->head, decomp->size, decomp->data, + session->header.needs_swap); if (!event) break; @@ -2100,7 +2110,7 @@ reader__process_events(struct reader *rd, struct perf_session *session, } more: - event = fetch_mmaped_event(session, head, mmap_size, buf); + event = fetch_mmaped_event(head, mmap_size, buf, session->header.needs_swap); if (IS_ERR(event)) return PTR_ERR(event); -- 2.20.1