Article View: gnu.gdb.bug
Article #381GDB 4.6 core dump reading dynamically-loaded object symtab
From: dwex
Date: Mon, 17 Aug 1992 20:29
Date: Mon, 17 Aug 1992 20:29
85 lines
4164 bytes
4164 bytes
GDB version: 4.6
Architecture/OS: Sun SparcStation ELC/SunOS 4.1.1
GDB Compiled With: GCC 2.2.2 (with demangling patch applied)
Application Compiled With: Unknown (probably stock Sun cc)
Description:
Used the 'sharedlibrary' command to force loading of dynamically
loaded object libraries in an Andrew application, after the
application died with a SIGSEGV. GDB dropped core with
SIGSEGV, dereferencing through a null pointer. Here's
the stack backtrace:
-----------------------------------------------------------------------------
#0 0x776e4 in read_dbx_symtab (section_offsets=0x42d0f0, objfile=0x41b308,
text_addr=0, text_size=8192) at ../../gdb-4.6/gdb/partial-stab.h:518
#1 0x7412c in dbx_symfile_read (objfile=0x41b308, section_offsets=0x42d0f0,
mainline=0) at ../../gdb-4.6/gdb/dbxread.c:482
#2 0x36960 in syms_from_objfile (objfile=0x41b308, addr=4149805056,
mainline=0, verbo=0) at ../../gdb-4.6/gdb/symfile.c:450
#3 0x36cd0 in symbol_file_add (
name=0x35f434 "/usr/add-on/andrew/dlib/atk/glist.do", from_tty=0,
addr=4149805056, mainline=0, mapped=0, readnow=0)
at ../../gdb-4.6/gdb/symfile.c:581
#4 0x56748 in symbol_add_stub (arg=0x35f408 "")
at ../../gdb-4.6/gdb/solib.c:674
#5 0x2478 in catch_errors (func=0x56710 <print_insn+5536>, args=0x35f408 "",
errstring=0x567a0 "Error while reading shared library symbols:\n")
at ../../gdb-4.6/gdb/main.c:367
#6 0x568dc in solib_add (arg_string=0x0, from_tty=1, target=0x0)
at ../../gdb-4.6/gdb/solib.c:728
#7 0x57208 in sharedlibrary_command (args=0x0, from_tty=1)
at ../../gdb-4.6/gdb/solib.c:1267
#8 0x3d90 in execute_command (p=0x14000d "", from_tty=1)
at ../../gdb-4.6/gdb/main.c:915
#9 0x4014 in command_loop () at ../../gdb-4.6/gdb/main.c:976
#10 0x3af4 in main (argc=2, argv=0xf7ffe70c) at ../../gdb-4.6/gdb/main.c:853
-------------------------------------------------------------------------------
Here's a patch that appears (at first glance) to solve the problem, or at
least work around it:
-------------------------------------------------------------------------------
*** ORIG/partial-stab.h Mon Aug 17 13:18:04 1992
--- partial-stab.h Mon Aug 17 13:20:00 1992
***************
*** 493,499 ****
#ifdef DBXREAD_ONLY
/* Kludges for ELF/STABS with Sun ACC */
last_function_name = namestring;
! if (pst->textlow == 0)
pst->textlow = CUR_SYMBOL_VALUE;
#if 0
if (startup_file_end == 0)
--- 493,499 ----
#ifdef DBXREAD_ONLY
/* Kludges for ELF/STABS with Sun ACC */
last_function_name = namestring;
! if (pst && pst->textlow == 0)
pst->textlow = CUR_SYMBOL_VALUE;
#if 0
if (startup_file_end == 0)
***************
*** 515,521 ****
#ifdef DBXREAD_ONLY
/* Kludges for ELF/STABS with Sun ACC */
last_function_name = namestring;
! if (pst->textlow == 0)
pst->textlow = CUR_SYMBOL_VALUE;
#if 0
if (startup_file_end == 0)
--- 515,521 ----
#ifdef DBXREAD_ONLY
/* Kludges for ELF/STABS with Sun ACC */
last_function_name = namestring;
! if (pst && pst->textlow == 0)
pst->textlow = CUR_SYMBOL_VALUE;
#if 0
if (startup_file_end == 0)
------------------------------------------------------------------------------
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David Wexelblat | dwex@mtgzfs3.att.com | Somebody get me a
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200 Laurel Ave - 4B-421 | |
Middletown, NJ 07748 | (908) 957-5871 | --Steve Miller Band
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Newsgroups: gnu.gdb.bug Path: arc1-ca.pugleaf.net!sparky!uunet!usc!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!mtgzy.UUCP!dwex From: dwex@mtgzy.UUCP Subject: GDB 4.6 core dump reading dynamically-loaded object symtab Message-ID: <9208172029.AA26872@mtgzfs3.att.com> Sender: gnulists@ai.mit.edu Organization: GNUs Not Usenet Distribution: gnu Date: Mon, 17 Aug 1992 20:29:10 GMT Approved: bug-gdb@prep.ai.mit.edu Lines: 86