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=-13.0 required=3.0 tests=BAYES_00,HK_RANDOM_FROM, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE 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 C465FC433E0 for ; Thu, 7 Jan 2021 05:10:37 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3603D225AC for ; Thu, 7 Jan 2021 05:10:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3603D225AC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bu.edu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39262 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kxNZE-0005mV-1g for qemu-devel@archiver.kernel.org; Thu, 07 Jan 2021 00:10:36 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35198) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kxNY2-0004vn-Du for qemu-devel@nongnu.org; Thu, 07 Jan 2021 00:09:23 -0500 Received: from relay64.bu.edu ([128.197.228.104]:45789) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kxNY0-0001rn-2a for qemu-devel@nongnu.org; Thu, 07 Jan 2021 00:09:21 -0500 X-Envelope-From: alxndr@bu.edu X-BU-AUTH: mozz.bu.edu [128.197.127.33] Received: from BU-AUTH (localhost.localdomain [127.0.0.1]) (authenticated bits=0) by relay64.bu.edu (8.14.3/8.14.3) with ESMTP id 10758J1W009767 (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Thu, 7 Jan 2021 00:08:23 -0500 Date: Thu, 7 Jan 2021 00:08:19 -0500 From: Alexander Bulekov To: Qiuhao Li Subject: Re: [PATCH v4 5/7] fuzz: set bits in operand of write/out to zero Message-ID: <20210107050819.heon7dfgfmhko4uw@mozz.bu.edu> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=128.197.228.104; envelope-from=alxndr@bu.edu; helo=relay64.bu.edu X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=0.999, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: thuth@redhat.com, qemu-devel@nongnu.org, darren.kenny@oracle.com, bsd@redhat.com, stefanha@redhat.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 201229 1240, Qiuhao Li wrote: > Simplifying the crash cases by opportunistically setting bits in operands of > out/write to zero may help to debug, since usually bit one means turn on or > trigger a function while zero is the default turn-off setting. > > Tested Bug 1908062. > > Signed-off-by: Qiuhao Li Reviewed-by: Alexander Bulekov > --- > scripts/oss-fuzz/minimize_qtest_trace.py | 39 ++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/scripts/oss-fuzz/minimize_qtest_trace.py b/scripts/oss-fuzz/minimize_qtest_trace.py > index 378a7ccec6..70ac0c5366 100755 > --- a/scripts/oss-fuzz/minimize_qtest_trace.py > +++ b/scripts/oss-fuzz/minimize_qtest_trace.py > @@ -164,6 +164,42 @@ def remove_minimizer(newtrace, outpath): > i += 1 > > > +def set_zero_minimizer(newtrace, outpath): > + # try setting bits in operands of out/write to zero > + i = 0 > + while i < len(newtrace): > + if (not newtrace[i].startswith("write ") and not > + newtrace[i].startswith("out")): > + i += 1 > + continue > + # write ADDR SIZE DATA > + # outx ADDR VALUE > + print("\nzero setting bits: {}".format(newtrace[i])) > + > + prefix = " ".join(newtrace[i].split()[:-1]) > + data = newtrace[i].split()[-1] > + data_bin = bin(int(data, 16)) > + data_bin_list = list(data_bin) > + > + for j in range(2, len(data_bin_list)): > + prior = newtrace[i] > + if (data_bin_list[j] == '1'): > + data_bin_list[j] = '0' > + data_try = hex(int("".join(data_bin_list), 2)) > + # It seems qtest only accepts padded hex-values. > + if len(data_try) % 2 == 1: > + data_try = data_try[:2] + "0" + data_try[2:-1] > + > + newtrace[i] = "{prefix} {data_try}\n".format( > + prefix=prefix, > + data_try=data_try) > + > + if not check_if_trace_crashes(newtrace, outpath): > + data_bin_list[j] = '1' > + newtrace[i] = prior > + i += 1 > + > + > def minimize_trace(inpath, outpath): > global TIMEOUT > with open(inpath) as f: > @@ -184,7 +220,10 @@ def minimize_trace(inpath, outpath): > old_len = len(newtrace) > remove_minimizer(newtrace, outpath) > newtrace = list(filter(lambda s: s != "", newtrace)) > + assert(check_if_trace_crashes(newtrace, outpath)) > > + # set zero minimizer > + set_zero_minimizer(newtrace, outpath) > assert(check_if_trace_crashes(newtrace, outpath)) > > > -- > 2.25.1 >