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, URIBL_BLOCKED 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 A133DC433E6 for ; Thu, 7 Jan 2021 04:54:56 +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 EDB1022D71 for ; Thu, 7 Jan 2021 04:54:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EDB1022D71 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]:36178 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kxNK2-0002rk-OO for qemu-devel@archiver.kernel.org; Wed, 06 Jan 2021 23:54:54 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:32956) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kxNJT-0002Qb-1f for qemu-devel@nongnu.org; Wed, 06 Jan 2021 23:54:19 -0500 Received: from relay64.bu.edu ([128.197.228.104]:45380) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kxNJQ-0003MW-Si for qemu-devel@nongnu.org; Wed, 06 Jan 2021 23:54:18 -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 1074rSZG032311 (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Wed, 6 Jan 2021 23:53:32 -0500 Date: Wed, 6 Jan 2021 23:53:28 -0500 From: Alexander Bulekov To: Qiuhao Li Subject: Re: [PATCH v4 4/7] fuzz: loop the remove minimizer and refactoring Message-ID: <20210107045328.owso2kow2gvqbdzq@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: > Now we use a one-time scan and remove strategy in the remval minimizer, > which is not suitable for timing dependent instructions. > > For example, instruction A will indicate an address where the config > chunk locates, and instruction B will make the configuration active. If > we have the following instruction sequence: > > ... > A1 > B1 > A2 > B2 > ... > > A2 and B2 are the actual instructions that trigger the bug. > > If we scan from top to bottom, after we remove A1, the behavior of B1 > might be unknowable, including not to crash the program. But we will > successfully remove B1 later cause A2 and B2 will crash the process > anyway: > > ... > A1 > A2 > B2 > ... > > Now one more trimming will remove A1. > > In the perfect case, we would need to be able to remove A and B (or C!) at > the same time. But for now, let's just add a loop around the minimizer. > > Since we only remove instructions, this iterative algorithm is converging. > > Tested with Bug 1908062. > > Signed-off-by: Qiuhao Li Small note below, but otherwise: Reviewed-by: Alexander Bulekov > --- > scripts/oss-fuzz/minimize_qtest_trace.py | 41 +++++++++++++++--------- > 1 file changed, 26 insertions(+), 15 deletions(-) > > diff --git a/scripts/oss-fuzz/minimize_qtest_trace.py b/scripts/oss-fuzz/minimize_qtest_trace.py > index 1a26bf5b93..378a7ccec6 100755 > --- a/scripts/oss-fuzz/minimize_qtest_trace.py > +++ b/scripts/oss-fuzz/minimize_qtest_trace.py > @@ -71,21 +71,9 @@ def check_if_trace_crashes(trace, path): > return False > > > -def minimize_trace(inpath, outpath): > - global TIMEOUT > - with open(inpath) as f: > - trace = f.readlines() > - start = time.time() > - if not check_if_trace_crashes(trace, outpath): > - sys.exit("The input qtest trace didn't cause a crash...") > - end = time.time() > - print("Crashed in {} seconds".format(end-start)) > - TIMEOUT = (end-start)*5 > - print("Setting the timeout for {} seconds".format(TIMEOUT)) > - > - i = 0 > - newtrace = trace[:] > +def remove_minimizer(newtrace, outpath): Maybe a different name for this function? e.g. minimize_each_line or minimize_iter -Alex > remove_step = 1 > + i = 0 > while i < len(newtrace): > # 1.) Try to remove lines completely and reproduce the crash. > # If it works, we're done. > @@ -174,7 +162,30 @@ def minimize_trace(inpath, outpath): > newtrace[i] = prior[0] > del newtrace[i+1] > i += 1 > - check_if_trace_crashes(newtrace, outpath) > + > + > +def minimize_trace(inpath, outpath): > + global TIMEOUT > + with open(inpath) as f: > + trace = f.readlines() > + start = time.time() > + if not check_if_trace_crashes(trace, outpath): > + sys.exit("The input qtest trace didn't cause a crash...") > + end = time.time() > + print("Crashed in {} seconds".format(end-start)) > + TIMEOUT = (end-start)*5 > + print("Setting the timeout for {} seconds".format(TIMEOUT)) > + > + newtrace = trace[:] > + > + # remove minimizer > + old_len = len(newtrace) + 1 > + while(old_len > len(newtrace)): > + old_len = len(newtrace) > + remove_minimizer(newtrace, outpath) > + newtrace = list(filter(lambda s: s != "", newtrace)) > + > + assert(check_if_trace_crashes(newtrace, outpath)) > > > if __name__ == '__main__': > -- > 2.25.1 >