From owner-freebsd-dtrace@FreeBSD.ORG Mon Dec 1 23:02:42 2014 Return-Path: Delivered-To: freebsd-dtrace@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 69272142; Mon, 1 Dec 2014 23:02:42 +0000 (UTC) Received: from mail-wi0-x22b.google.com (mail-wi0-x22b.google.com [IPv6:2a00:1450:400c:c05::22b]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id DC04374B; Mon, 1 Dec 2014 23:02:41 +0000 (UTC) Received: by mail-wi0-f171.google.com with SMTP id bs8so26298695wib.4 for ; Mon, 01 Dec 2014 15:02:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc:content-type; bh=FrMH3YrDCKxQbfihsSMumtrUR1DarDfHC6atOH4lOlk=; b=YPKicyprulefOqFWlQhvqW+B2BDUqiCId90Pfno52u5fGgN2MEB5i3+tgfOs+oopGd Ao1WycK9ot9150gfS3zXfPnJ23PTA6JhavNkZMiT9RCRCY/8wOgQCyfmjW05W6ajPYd7 EcuhFHsi+xrsihKpioH2e1uDcGRl3rd7yuKmqaC55t+xPdhoexbGn623JCs61IZ+Wnc1 xzNADPOI8Gs83QOp+3BSqMRJR+GXCEIUCEbSdfiknxInHJ8rKjWjXyONAr58W6Ymzdem ZulV9K8/AJ1yiPy7SRltpFjxtF7CUxAV7ZkGmGgDKflZGUiEvQDGffo+whuQwinqX+9F oJlw== X-Received: by 10.194.83.8 with SMTP id m8mr98954181wjy.58.1417474960178; Mon, 01 Dec 2014 15:02:40 -0800 (PST) MIME-Version: 1.0 Sender: fedor.indutny@gmail.com Received: by 10.27.48.2 with HTTP; Mon, 1 Dec 2014 15:02:19 -0800 (PST) In-Reply-To: <20141201215430.GD48232@charmander.picturesperfect.net> References: <20140227050136.GB28089@raichu> <20141201215430.GD48232@charmander.picturesperfect.net> From: Fedor Indutny Date: Tue, 2 Dec 2014 03:02:19 +0400 X-Google-Sender-Auth: yMacemQw4BRrSPtL7AgU9TSV2uI Message-ID: Subject: Re: DTrace fixes for node.js To: Mark Johnston Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 Cc: "freebsd-dtrace@freebsd.org" X-BeenThere: freebsd-dtrace@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "A discussion list for developers working on DTrace in FreeBSD." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Dec 2014 23:02:42 -0000 Mark, Yes, 271413 is the one fixing PROGBITS. Anyway, my patch should support both PROGBITS and DOFW_sun, making it quite universal. Thank you for your time! Fedor. On Tue, Dec 2, 2014 at 12:54 AM, Mark Johnston wrote: > On Mon, Dec 01, 2014 at 04:59:02PM +0400, Fedor Indutny wrote: > > Hello Mark, DTrace people! > > > > Hi Fedor, > > > Hope you are doing well. > > > > Looks like FreeBSD 10.1 decided to play some not that funny games > > with drti.c again :) > > > > I have submitted a [patch][0] as a problem report. > > Thank you. I'll test and commit it if I don't run into any problems. > > > > > It fixes iteration over aligned DOFs, and accounts for a > > non-master-branch FreeBSD stuff in: > > > > cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c > > > > Which is currently producing SHT_PROGBITS section instead of > > expected SHT_SUNW_dof, thus confusing the drti.c file. > > Hm, are you referring to this change: > https://svnweb.freebsd.org/base?view=revision&revision=271413 > ? > > I'm a bit confused, as it hasn't been merged to 10 yet: it exposed > another dtrace bug that caused build failures in some USDT-enabled > ports, so I'm waiting for the subsequent fixes to settle. > > -Mark > > > > > Thank you, > > Fedor. > > > > [0]: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=195555 > > > > > > On Thu, Feb 27, 2014 at 6:50 PM, Fedor Indutny > wrote: > > > > > Update sent, thank you! > > > > > > On Thu, Feb 27, 2014 at 6:39 PM, Mark Johnston > wrote: > > > > On Thu, Feb 27, 2014 at 3:30 AM, Fedor Indutny > > > wrote: > > > >> Mark, > > > >> > > > >> Thanks for looking into this. I just tried your patch and it (no > > > >> surprise) builds fine. Node.js DOF symbols seems to be resolving > > > >> properly too! > > > >> > > > >> Do you want me to squash this changes into my patch, and post them > on > > > >> that ticket? > > > >> > > > > > > > > That would be good, thanks. When I have some time I'll do more > testing > > > > and commit the change. > > > > > > > > -Mark > > > > > > > >> On Thu, Feb 27, 2014 at 9:01 AM, Mark Johnston > > > wrote: > > > >>> On Tue, Feb 25, 2014 at 06:16:15PM +0400, Fedor Indutny wrote: > > > >>>> Hello devs! > > > >>>> > > > >>>> I have made some fixes to fix DTrace support for node.js in > FreeBSD: > > > >>>> > > > >>>> * http://www.freebsd.org/cgi/query-pr.cgi?pr=186821 > > > >>>> * http://www.freebsd.org/cgi/query-pr.cgi?pr=187027 > > > >>>> > > > >>>> Here is a blog post with a bit of explanation of why this is > needed > > > >>>> and what is fixed: https://blog.indutny.com/7.freebsd-dtrace > > > >>>> > > > >>>> Please let me know if I could be any help in reviewing it. > > > >>> > > > >>> Hi Fedor, > > > >>> > > > >>> The DOF limit change looks fine to me. I note that the illumos guys > > > have > > > >>> just pushed a change to illumos-gate which bumps > dtrace_dof_maxsize, > > > but > > > >>> it's good to have the sysctl as well. > > > >>> > > > >>> The drti change looks mostly good to me. The real problem there is > that > > > >>> our linker doesn't know how to merge DOF, so it just concatenates > the > > > >>> tables into one SUNW_dof section. So we should really fix our > linker, > > > >>> but it doesn't hurt to also handle the problem in drti.o. > > > >>> > > > >>> There are a couple of bugs in the patch. First, the "break" added > after > > > >>> finding the DOF section causes problems if we haven't yet seen the > > > >>> symbol table. Second, fixedprobes needs to be reset at the > beginning of > > > >>> each iteration of the while loop that you added, else we may not > try > > > >>> searching the dynamic symbol table when fixing the probe addresses. > > > I've > > > >>> pasted a patch below; could you test it and make sure things still > work > > > >>> properly with node? > > > >>> > > > >>> Thanks for the detailed blog post and problem description, they > were > > > >>> very helpful. :) > > > >>> > > > >>> -Mark > > > >>> > > > >>> diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/drti.c > > > b/cddl/contrib/opensolaris/lib/libdtrace/common/drti.c > > > >>> index e47cfb4d..bb02d8c 100644 > > > >>> --- a/cddl/contrib/opensolaris/lib/libdtrace/common/drti.c > > > >>> +++ b/cddl/contrib/opensolaris/lib/libdtrace/common/drti.c > > > >>> @@ -162,7 +162,7 @@ dtrace_dof_init(void) > > > >>> char *dofstrtabraw; > > > >>> size_t shstridx, symtabidx = 0, dynsymidx = 0; > > > >>> unsigned char *buf; > > > >>> - int fixedprobes = 0; > > > >>> + int fixedprobes; > > > >>> #endif > > > >>> > > > >>> if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL) > > > >>> @@ -214,7 +214,6 @@ dtrace_dof_init(void) > > > >>> if (s && strcmp(s, ".SUNW_dof") == 0) { > > > >>> dofdata = elf_getdata(scn, NULL); > > > >>> dof = dofdata->d_buf; > > > >>> - break; > > > >>> } > > > >>> } > > > >>> } > > > >>> @@ -226,6 +225,7 @@ dtrace_dof_init(void) > > > >>> } > > > >>> > > > >>> while ((char *) dof < (char *) dofdata->d_buf + > > > dofdata->d_size) { > > > >>> + fixedprobes = 0; > > > >>> dof_next = (void *) ((char *) dof + > dof->dofh_filesz); > > > >>> #endif > > > >>> > > > >