From owner-freebsd-bugs@FreeBSD.ORG Wed Sep 13 03:30:19 2006 Return-Path: X-Original-To: freebsd-bugs@hub.freebsd.org Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7277316A40F for ; Wed, 13 Sep 2006 03:30:19 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by mx1.FreeBSD.org (Postfix) with ESMTP id E3E0743D49 for ; Wed, 13 Sep 2006 03:30:18 +0000 (GMT) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.13.4/8.13.4) with ESMTP id k8D3UIgf006200 for ; Wed, 13 Sep 2006 03:30:18 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.13.4/8.13.4/Submit) id k8D3UIx9006199; Wed, 13 Sep 2006 03:30:18 GMT (envelope-from gnats) Resent-Date: Wed, 13 Sep 2006 03:30:18 GMT Resent-Message-Id: <200609130330.k8D3UIx9006199@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Zhouyi Zhou Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D393F16A403 for ; Wed, 13 Sep 2006 03:28:56 +0000 (UTC) (envelope-from nobody@FreeBSD.org) Received: from www.freebsd.org (www.freebsd.org [216.136.204.117]) by mx1.FreeBSD.org (Postfix) with ESMTP id A354D43D45 for ; Wed, 13 Sep 2006 03:28:56 +0000 (GMT) (envelope-from nobody@FreeBSD.org) Received: from www.freebsd.org (localhost [127.0.0.1]) by www.freebsd.org (8.13.1/8.13.1) with ESMTP id k8D3SpdF074186 for ; Wed, 13 Sep 2006 03:28:51 GMT (envelope-from nobody@www.freebsd.org) Received: (from nobody@localhost) by www.freebsd.org (8.13.1/8.13.1/Submit) id k8D3SpEf074185; Wed, 13 Sep 2006 03:28:51 GMT (envelope-from nobody) Message-Id: <200609130328.k8D3SpEf074185@www.freebsd.org> Date: Wed, 13 Sep 2006 03:28:51 GMT From: Zhouyi Zhou To: freebsd-gnats-submit@FreeBSD.org X-Send-Pr-Version: www-2.3 Cc: Subject: kern/103207: kdb_backtrace core dump and a settlement X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Sep 2006 03:30:19 -0000 >Number: 103207 >Category: kern >Synopsis: kdb_backtrace core dump and a settlement >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed Sep 13 03:30:18 GMT 2006 >Closed-Date: >Last-Modified: >Originator: Zhouyi Zhou >Release: FreeBSD 6.0 >Organization: Institute of Software, Chinese Academy of Sciences >Environment: FreeBSD 6.0-RELEASE FreeBSD 6.0-RELEASE #41: Wed Sep 13 11:08:04 UTC 2006 >Description: The FreeBSD's DDB backtrace mechanism has a small bug on it. sys/ddb/db_sym.c 249 void 250 db_symbol_values(sym, namep, valuep) 251 c_db_sym_t sym; 252 const char **namep; 253 db_expr_t *valuep; 254 { 255 db_expr_t value; 256 257 if (sym == DB_SYM_NULL) { 258 *namep = 0; 259 return; 260 } 261 262 X_db_symbol_values(db_last_symtab, sym, namep, &value); 263 264 if (db_symbol_is_ambiguous(sym)) 265 *namep = db_qualify(sym, db_last_symtab->name); 266 if (valuep) 267 *valuep = value; 268 } sometimes the db_last_symtab will be 0 because of symbol lookup failure in previous stages, this will cause kernel to dump. >How-To-Repeat: add configuration option that will trigger kdb_backtrace such as options WITNESS_KDB to kernel configuration file >Fix: My modification is: 257 if (sym == DB_SYM_NULL||db_last_symtab==0) { This seems to settle the problem >Release-Note: >Audit-Trail: >Unformatted: