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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 80C05C7618F for ; Fri, 26 Jul 2019 20:46:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 466F9218B8 for ; Fri, 26 Jul 2019 20:46:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=maine.edu header.i=@maine.edu header.b="d41BIaTH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727948AbfGZUq6 (ORCPT ); Fri, 26 Jul 2019 16:46:58 -0400 Received: from mail-qt1-f193.google.com ([209.85.160.193]:33666 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726554AbfGZUq5 (ORCPT ); Fri, 26 Jul 2019 16:46:57 -0400 Received: by mail-qt1-f193.google.com with SMTP id r6so49723658qtt.0 for ; Fri, 26 Jul 2019 13:46:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=maine.edu; s=google; h=from:date:to:cc:subject:message-id:user-agent:mime-version; bh=EkkYyzbKFCkkMpgaoYMPHhbpzI2gyifZuS1BV3t9ELc=; b=d41BIaTHJGxt3X6jmm1ZiRmCWH3HgmROD5JE/8Y/Dlhw0fXAlsi+y4Paiin55JriCt aDf6CbiXAyC4ABcTDSiiAYf38ABXWtJ/MyNFWnewdNN0VcFzfLv/WPtAzjQpbQ31/xJP nXESVzSPK71H1Fi9VXpcwEEjxfmsrF55Fp9AE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:user-agent :mime-version; bh=EkkYyzbKFCkkMpgaoYMPHhbpzI2gyifZuS1BV3t9ELc=; b=A3V5uyUuBXrKooGjox3HE6KfuYnVyB84uOGFHuMIYGhSjIhwi9lA07cfUAm5D/EQO1 jgWQI0OGUz0PVV/Ti8aV1MfINnvx+hjDkt/DlAHnzLlID/Qa4qFNz0/j2wQ8COYav3pe 7eLyTwSqSY37mThwRhhpiYeGhHDcRbqpZ50UPlmyUq5+cyaBbh6zRVyhhqfUJTOM7W4w AU6+drmAsgwuvRxI/WYMx2RgsduSkw/Gegjrun7vRexqLhoqXFfnmXv0Kx4cMo+5OlfQ 8NGjfqBjzn/8QXRhP7Esw8qnnh2aRaeDCc/5N55ZGDajRNe2g8phnlr/vyNDWzUPohWw JkOw== X-Gm-Message-State: APjAAAUFhIzBO5ciLjJ+00AUycZSNG2gVwimJGVbA9GdnpZLxykCzRHr mswLIAtsUfdzQhC6rnMiBawRyA== X-Google-Smtp-Source: APXvYqxl7ywmGwEFcDCqiOH+BMZ8HfahC2V2j0Z79GYZvbYMRgHy7PZ75ZCehW1ufCcDBaNlQDBIsA== X-Received: by 2002:aed:34a6:: with SMTP id x35mr67957114qtd.187.1564174016913; Fri, 26 Jul 2019 13:46:56 -0700 (PDT) Received: from macbook-air (weaver.eece.maine.edu. [130.111.218.23]) by smtp.gmail.com with ESMTPSA id b13sm33271374qtk.55.2019.07.26.13.46.55 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 26 Jul 2019 13:46:55 -0700 (PDT) From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Fri, 26 Jul 2019 16:46:51 -0400 (EDT) X-X-Sender: vince@macbook-air To: Arnaldo Carvalho de Melo cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Alexander Shishkin , Jiri Olsa , Namhyung Kim Subject: perf: perf report stuck in an infinite loop Message-ID: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently the perf_data_fuzzer causes perf report to get stuck in an infinite loop. >From what I can tell, the issue happens in reader__process_events() when an event is mapped using mmap(), but when it goes to process the event finds out the internal event header has the size (invalidly) set to something much larger than the mmap buffer size. This means fetch_mmaped_event() fails, which gotos remap: which tries again with the exact same mmap size, and this will loop forever. I haven't been able to puzzle out how to fix this, but maybe you have a better feel for what's going on here. Vince