From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff King Subject: Re: regression in multi-threaded git-pack-index Date: Tue, 19 Mar 2013 05:59:43 -0400 Message-ID: <20130319095943.GA6031@sigill.intra.peff.net> References: <20130315224240.50AA340839@wince.sfo.corp.google.com> <20130316114118.GA1940@sigill.intra.peff.net> <87fvzrajmr.fsf@pctrast.inf.ethz.ch> <20130319093034.GA29997@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Stefan Zager , git@vger.kernel.org, =?utf-8?B?Tmd1eeG7hW4gVGjDoWkgTmfhu41j?= Duy To: Thomas Rast X-From: git-owner@vger.kernel.org Tue Mar 19 11:00:16 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UHtL5-0002En-39 for gcvg-git-2@plane.gmane.org; Tue, 19 Mar 2013 11:00:15 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756672Ab3CSJ7t (ORCPT ); Tue, 19 Mar 2013 05:59:49 -0400 Received: from 75-15-5-89.uvs.iplsin.sbcglobal.net ([75.15.5.89]:58128 "EHLO peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756266Ab3CSJ7s (ORCPT ); Tue, 19 Mar 2013 05:59:48 -0400 Received: (qmail 26938 invoked by uid 107); 19 Mar 2013 10:01:31 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) (smtp-auth username relayok, mechanism cram-md5) by peff.net (qpsmtpd/0.84) with ESMTPA; Tue, 19 Mar 2013 06:01:31 -0400 Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Tue, 19 Mar 2013 05:59:43 -0400 Content-Disposition: inline In-Reply-To: <20130319093034.GA29997@sigill.intra.peff.net> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Tue, Mar 19, 2013 at 05:30:34AM -0400, Jeff King wrote: > On Tue, Mar 19, 2013 at 09:17:32AM +0100, Thomas Rast wrote: > > > > but the line in question is: > > > > > > if (deepest_delta < delta_obj->delta_depth) > > > > > > And in the debugger, both of those variables appear to have sane values > > > (nor should either impacted by the patch you bisected to). On top of > > > that, running with pack.threads=1 produces the same error. So I think it > > > may be a false positive from valgrind, and unrelated to your issue. > > > > I find that somewhat unlikely, for two reasons: memcheck is actually > > quite good at finding uninitialized memory use, it just isn't that good > > at distinguishing if it makes a difference. Most false positives are of > > the "loading an entire word and discarding most of it" kind. > > Yes, that has been my experience with valgrind false positives, too. But > if this is a real problem, it may be different from the OP's issue. It > seems to trigger for me in v1.7.10, before Duy's threading patches. It > does not seem to be in v1.7.5. I'm bisecting now. Hmph. It bisects to Junio's d1a0ed1 (index-pack: show histogram when emulating "verify-pack -v", 2011-06-03), which introduces those lines. The deepest_delta variable is static, so by definition it is always initialized to something. So I guess some objects may not have delta_depth set. Still looking. -Peff