From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.7 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id C2ADF208CD for ; Sun, 20 Aug 2017 10:06:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751726AbdHTKGg (ORCPT ); Sun, 20 Aug 2017 06:06:36 -0400 Received: from cloud.peff.net ([104.130.231.41]:44002 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751088AbdHTKGg (ORCPT ); Sun, 20 Aug 2017 06:06:36 -0400 Received: (qmail 29067 invoked by uid 109); 20 Aug 2017 10:06:35 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Sun, 20 Aug 2017 10:06:35 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 13429 invoked by uid 111); 20 Aug 2017 10:07:02 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.94) with SMTP; Sun, 20 Aug 2017 06:07:02 -0400 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Sun, 20 Aug 2017 06:06:34 -0400 Date: Sun, 20 Aug 2017 06:06:34 -0400 From: Jeff King To: Martin =?utf-8?B?w4VncmVu?= Cc: git@vger.kernel.org Subject: Re: [PATCH/RFC 0/5] Some ThreadSanitizer-results Message-ID: <20170820100633.ehn2sc7gwmm6lftd@sigill.intra.peff.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Tue, Aug 15, 2017 at 02:53:00PM +0200, Martin Ågren wrote: > I tried running the test suite on Git compiled with ThreadSanitizer > (SANITIZE=thread). Maybe this series could be useful for someone else > trying to do the same. I needed the first patch to avoid warnings when > compiling, although it actually has nothing to do with threads. > > The last four patches are about avoiding some issues where > ThreadSanitizer complains for reasonable reasons, but which to the best > of my understanding are not real problems. These patches could be useful > to make "actual" problems stand out more. Of course, if no-one ever runs > ThreadSanitizer, they are of little to no (or even negative) value... I think it's a chicken-and-egg. I'd love to run the test suite with tsan from time to time, but there's no point if it turns up a bunch of false positives. The general direction here looks good to me (and I agree with the comments made so far, especially that we should stop writing to strbuf_slopbuf entirely). > ThreadSanitizer: add suppressions This one is the most interesting because it really is just papering over the issues. I "solved" the transfer_debug one with actual code in: https://public-inbox.org/git/20170710133040.yom65mjol3nmf2it@sigill.intra.peff.net/ but it just feels really dirty. I'd be inclined to go with suppressions for now until somebody can demonstrate or argue for an actual breakage (just because it makes the tool more useful for finding _real_ problems). -Peff