From owner-freebsd-dtrace@FreeBSD.ORG Tue Nov 25 02:36:28 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 DA9C3923; Tue, 25 Nov 2014 02:36:27 +0000 (UTC) Received: from mail-ig0-x22d.google.com (mail-ig0-x22d.google.com [IPv6:2607:f8b0:4001:c05::22d]) (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 9FC59A01; Tue, 25 Nov 2014 02:36:27 +0000 (UTC) Received: by mail-ig0-f173.google.com with SMTP id r2so4281568igi.6 for ; Mon, 24 Nov 2014 18:36:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=LCZxffryjKxSWWqZi7tOdjpt0mQZ8pX6UG2MprIt+qU=; b=QDjD78Ham9Hrj8C+XnAOzOSFSETjlfO9BDPPrHaQHtF2u9F11SEl9yKg2AGZsIXBGG afjgPyZTjBONSx/3hIQtEvm4ogTg8vg0BlF0iq0dOA05ObzrhyKSwKLaT8STvCr1/unJ UWwPEHhShw5mlNHB8rYqlYPKHE3EuF+8UGmC1cxnRBX4ZghOfu4+dHDyNETI6eC/TDGw xFOAnSRxtVIaILv99IzsOc62RXXb1ZyMiDndWkXLBPcgpd89msJnzCeDcy3PtQVCGtaL qZ/uPD+8IkxqgkxwPJCB6uMM6AHOoWHhDcITOi0lWdsmT+oh93uABlvcJAIpQG1awBO5 EMMw== MIME-Version: 1.0 X-Received: by 10.107.26.193 with SMTP id a184mr7247435ioa.80.1416882986858; Mon, 24 Nov 2014 18:36:26 -0800 (PST) Received: by 10.107.9.13 with HTTP; Mon, 24 Nov 2014 18:36:26 -0800 (PST) In-Reply-To: <20141123021856.GA54708@raichu> References: <20141109093632.GV53947@kib.kiev.ua> <9011F920-3092-4E61-9CDC-68FD9092BB7D@me.com> <201411131336.12334.jhb@freebsd.org> <20141123021856.GA54708@raichu> Date: Mon, 24 Nov 2014 18:36:26 -0800 Message-ID: Subject: Re: DTrace: stack() does not print kernel module functions for i386 From: Shrikanth Kamath To: Mark Johnston Content-Type: text/plain; charset=UTF-8 Cc: John Baldwin , Rui Paulo , freebsd-hackers@freebsd.org, avg@freebsd.org, Konstantin Belousov , 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: Tue, 25 Nov 2014 02:36:28 -0000 > The suggested patch doesn't seem quite right; there are other functions > in dt_module.c with the same assignment (i.e. > "is_elf_obj = ehdr.e_type == ET_REL"), but the same modification is not > correct in all cases - fixing it everywhere breaks stack() again - and > "is_elf_obj" seems like the wrong name if DSOs are counted as well. > > The root of the problem is that dmp->dm_*_va offsets don't have the kld > load address taken into account on i386, since they're currently set based > only on the ELF section addresses. This is handled by > dmp->dm_reloc_offset for symbols, but that's a separate case. > > When is_elf_obj is true, we include the load address when setting the > dmp->dm_*_va fields. I suggest we do that unconditionally, and only set > elements of dmp->dm_sec_offsets if is_elf_obj is true. This fixes the > bug for me on i386. Any opinions? > > Thanks, > -Mark > > diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_module.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_module.c > index e3905c1..9dd52b5 100644 > --- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_module.c > +++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_module.c > @@ -1211,13 +1211,13 @@ dt_module_update(dtrace_hdl_t *dtp, struct kld_file_stat *k_stat) > #if defined(__FreeBSD__) > if (sh.sh_size == 0) > continue; > - if (is_elf_obj && (sh.sh_type == SHT_PROGBITS || > - sh.sh_type == SHT_NOBITS)) { > + if (sh.sh_type == SHT_PROGBITS || sh.sh_type == SHT_NOBITS) { > alignmask = sh.sh_addralign - 1; > mapbase += alignmask; > mapbase &= ~alignmask; > sh.sh_addr = mapbase; > - dmp->dm_sec_offsets[elf_ndxscn(sp)] = sh.sh_addr; > + if (is_elf_obj) > + dmp->dm_sec_offsets[elf_ndxscn(sp)] = sh.sh_addr; > mapbase += sh.sh_size; > } > #endif Hello Mark, I tested the patch and works good, did some basic testing. Marcel too pointed to the other occurrence of is_elf_obj in the file and that it should not include ET_DYN which is when I realized it was not the right thing to do, i was trying to read up more on this, guess this patch takes care of it. Thanks for fixing this. Thanks, -- Shrikanth R K