From owner-freebsd-hackers@FreeBSD.ORG Sun Nov 23 02:19:02 2014 Return-Path: Delivered-To: freebsd-hackers@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 39CC040B; Sun, 23 Nov 2014 02:19:02 +0000 (UTC) Received: from mail-pd0-x22a.google.com (mail-pd0-x22a.google.com [IPv6:2607:f8b0:400e:c02::22a]) (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 02A1E2E1; Sun, 23 Nov 2014 02:19:02 +0000 (UTC) Received: by mail-pd0-f170.google.com with SMTP id fp1so7644240pdb.15 for ; Sat, 22 Nov 2014 18:19:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=WaThMR+dukbH29fNT1r4EJZvXYUHoFv/hjprvhgCeyM=; b=Q+itBFCOPFhGGTnQiqg/S/sNY1LWyRJBXPLqz4kWk+8emewA4XdejjdbYwBpQMbuny HRjMbJrTNdgIdZjV4k/ZUs2X830pj8ZvePi1FE0DZeELP7cBZzHQ7eVe6G7GHHfXhA3L g42b4X+q7EKNYob/mUyVuon4Iqc4JGv6fBBhokuEv0ltmRlDggVkUpnEx6vRrUb6dUdW GvAH3UfHpiRI7QfEHDGR81Gj06rBqR4OJ/45+cR2SC3gJL4tLcmGiVb10w5H+7Q0Yl66 Lg7OALzlUx6NJdx9PFxu0fK2+2RqoyenuKs913QupGOPDfwCc7QFhM3BAx7+EpfrAlhk hWbA== X-Received: by 10.69.16.99 with SMTP id fv3mr20258545pbd.43.1416709141581; Sat, 22 Nov 2014 18:19:01 -0800 (PST) Received: from raichu ([198.244.104.6]) by mx.google.com with ESMTPSA id oq6sm8557860pdb.45.2014.11.22.18.19.00 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 22 Nov 2014 18:19:00 -0800 (PST) Sender: Mark Johnston Date: Sat, 22 Nov 2014 18:18:56 -0800 From: Mark Johnston To: Rui Paulo Subject: Re: DTrace: stack() does not print kernel module functions for i386 Message-ID: <20141123021856.GA54708@raichu> References: <20141109093632.GV53947@kib.kiev.ua> <9011F920-3092-4E61-9CDC-68FD9092BB7D@me.com> <201411131336.12334.jhb@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Cc: Shrikanth Kamath , freebsd-hackers@freebsd.org, avg@freebsd.org, Konstantin Belousov , freebsd-dtrace@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 23 Nov 2014 02:19:02 -0000 On Thu, Nov 13, 2014 at 07:49:27PM -0800, Rui Paulo wrote: > On Nov 13, 2014, at 10:36, John Baldwin wrote: > > Why have the #ifdef? In theory other platforms besides amd64 could use > > sys/kern/link_elf_obj.c. It doesn't hurt to just let the code always accept > > both ET_DYN and ET_REL does it? > > No, it doesn't hurt. 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