abort() missing return-address => useless core file

Fri Nov 4 14:13:32 UTC 2011

On 2011-11-04, Bernhard Reutner-Fischer <rep.dot.nop at gmail.com> wrote:
> On 3 November 2011 14:23, Grant Edwards <grant.b.edwards at gmail.com> wrote:
>> It appears that the abort() function somehow breaks the resulting
>> corefile so that you can't do a post-mortem backtrace. ?I suspect that
>> gcc has figured out that the abort() function never returns, so it
>> doesn't push a return address onto the stack.
>>
>> I've managed to work around the problem by doing something like this
>> to cause a segfault instead of calling abort():
>>
>> ?*((volatile char*)0) = 0;
>>
>> That produces a usable core file.
>>
>> But, it would be nice if abort() could be "fixed" somehow...
>
> Works for me. What exactly do you see? What arch? .config?

ARM926

Config file below.

>From what I've googled, this was also a problem for glibc on ARM. It
probably wouldn't be a problem on architectures where a subroutine
call instruction automatically pushes the return address onto the
stack (such as IA32).

ARM doesn't do that.  An ARM subroutine call instruction puts the
return address in a register (R14, IIRC).  If the called function
needs to use R14 for anything, the called function has to push it onto
the stack manually in its function preamble.  I presume that if you
tell gcc that abort() doesn't return, then it won't push the return
address onto the stack and therefore no backtrace.

Do we really need to try to save one instruction and one word of stack
space when the program is about to terminate?

------------------------------uClibc.config------------------------------
#
# Automatically generated make config: don't edit
# Version: 0.9.30.2
# Tue Apr 13 14:18:15 2010
#
# TARGET_alpha is not set
TARGET_arm=y
# TARGET_avr32 is not set
# TARGET_bfin is not set
# TARGET_cris is not set
# TARGET_e1 is not set
# TARGET_frv is not set
# TARGET_h8300 is not set
# TARGET_hppa is not set
# TARGET_i386 is not set
# TARGET_i960 is not set
# TARGET_ia64 is not set
# TARGET_m68k is not set
# TARGET_microblaze is not set
# TARGET_mips is not set
# TARGET_nios is not set
# TARGET_nios2 is not set
# TARGET_powerpc is not set
# TARGET_sh is not set
# TARGET_sh64 is not set
# TARGET_sparc is not set
# TARGET_v850 is not set
# TARGET_vax is not set
# TARGET_x86_64 is not set
# TARGET_xtensa is not set

#
# Target Architecture Features and Options
#
TARGET_ARCH="arm"
FORCE_OPTIONS_FOR_ARCH=y
# CONFIG_ARM_OABI is not set
CONFIG_ARM_EABI=y
CONFIG_GENERIC_ARM=y
# CONFIG_ARM610 is not set
# CONFIG_ARM710 is not set
# CONFIG_ARM7TDMI is not set
# CONFIG_ARM720T is not set
# CONFIG_ARM920T is not set
# CONFIG_ARM922T is not set
# CONFIG_ARM926T is not set
# CONFIG_ARM10T is not set
# CONFIG_ARM1136JF_S is not set
# CONFIG_ARM1176JZ_S is not set
# CONFIG_ARM1176JZF_S is not set
# CONFIG_ARM_CORTEX_M3 is not set
# CONFIG_ARM_CORTEX_M1 is not set
# CONFIG_ARM_SA110 is not set
# CONFIG_ARM_SA1100 is not set
# CONFIG_ARM_XSCALE is not set
# CONFIG_ARM_IWMMXT is not set
TARGET_SUBARCH=""

#
# Using ELF file format
#
ARCH_ANY_ENDIAN=y
ARCH_LITTLE_ENDIAN=y
# ARCH_WANTS_BIG_ENDIAN is not set
ARCH_WANTS_LITTLE_ENDIAN=y
ARCH_HAS_MMU=y
ARCH_USE_MMU=y
UCLIBC_HAS_FLOATS=y
# UCLIBC_HAS_FPU is not set
UCLIBC_HAS_SOFT_FLOAT=y
DO_C99_MATH=y
UCLIBC_HAS_FENV=y
KERNEL_HEADERS="/home/nextgen/crosstool-ng/toolchain/arm-unknown-linux-uclibcgnueabi//sys-root/usr/include"
HAVE_DOT_CONFIG=y

#
# General Library Settings
#
# HAVE_NO_PIC is not set
DOPIC=y
# ARCH_HAS_NO_SHARED is not set
# ARCH_HAS_NO_LDSO is not set
HAVE_SHARED=y
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LDSO_CACHE_SUPPORT=y
# LDSO_PRELOAD_FILE_SUPPORT is not set
LDSO_BASE_FILENAME="ld.so"
UCLIBC_STATIC_LDCONFIG=y
# LDSO_RUNPATH is not set
UCLIBC_CTOR_DTOR=y
# LDSO_GNU_HASH_SUPPORT is not set
# HAS_NO_THREADS is not set
UCLIBC_HAS_THREADS=y
PTHREADS_DEBUG_SUPPORT=y
LINUXTHREADS_OLD=y
UCLIBC_HAS_SYSLOG=y
UCLIBC_HAS_LFS=y
# MALLOC is not set
# MALLOC_SIMPLE is not set
MALLOC_STANDARD=y
# MALLOC_GLIBC_COMPAT is not set
UCLIBC_DYNAMIC_ATEXIT=y
# COMPAT_ATEXIT is not set
UCLIBC_SUSV3_LEGACY=y
# UCLIBC_SUSV3_LEGACY_MACROS is not set
# UCLIBC_HAS_STUBS is not set
UCLIBC_HAS_SHADOW=y
UCLIBC_HAS_PROGRAM_INVOCATION_NAME=y
UCLIBC_HAS___PROGNAME=y
UCLIBC_HAS_PTY=y
ASSUME_DEVPTS=y
UNIX98PTY_ONLY=y
# UCLIBC_HAS_GETPT is not set
UCLIBC_HAS_TM_EXTENSIONS=y
UCLIBC_HAS_TZ_CACHING=y
UCLIBC_HAS_TZ_FILE=y
UCLIBC_HAS_TZ_FILE_READ_MANY=y
UCLIBC_TZ_FILE_PATH="/etc/TZ"

#
# Advanced Library Settings
#
UCLIBC_PWD_BUFFER_SIZE=256
UCLIBC_GRP_BUFFER_SIZE=256

#
# Support various families of functions
#
UCLIBC_LINUX_MODULE_24=y
UCLIBC_LINUX_SPECIFIC=y
UCLIBC_HAS_GNU_ERROR=y
# UCLIBC_BSD_SPECIFIC is not set
UCLIBC_HAS_BSD_ERR=y
# UCLIBC_HAS_OBSOLETE_BSD_SIGNAL is not set
# UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL is not set
# UCLIBC_NTP_LEGACY is not set
# UCLIBC_SV4_DEPRECATED is not set
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UCLIBC_HAS_ADVANCED_REALTIME=y
UCLIBC_HAS_EPOLL=y
UCLIBC_HAS_XATTR=y
UCLIBC_HAS_PROFILING=y
UCLIBC_HAS_CRYPT_IMPL=y
UCLIBC_HAS_CRYPT=y
UCLIBC_HAS_NETWORK_SUPPORT=y
UCLIBC_HAS_SOCKET=y
UCLIBC_HAS_IPV4=y
# UCLIBC_HAS_IPV6 is not set
UCLIBC_HAS_RPC=y
UCLIBC_HAS_FULL_RPC=y
UCLIBC_HAS_REENTRANT_RPC=y
UCLIBC_USE_NETLINK=y
UCLIBC_SUPPORT_AI_ADDRCONFIG=y
# UCLIBC_HAS_BSD_RES_CLOSE is not set

#
# String and Stdio Support
#
UCLIBC_HAS_STRING_GENERIC_OPT=y
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# UCLIBC_HAS_CTYPE_UNSAFE is not set
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# UCLIBC_HAS_LOCALE is not set
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# UCLIBC_HAS_STDIO_BUFSIZ_8192 is not set
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# UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8 is not set
# UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT is not set
UCLIBC_HAS_STDIO_GETC_MACRO=y
UCLIBC_HAS_STDIO_PUTC_MACRO=y
UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION=y
# UCLIBC_HAS_FOPEN_LARGEFILE_MODE is not set
# UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE is not set
# UCLIBC_HAS_GLIBC_CUSTOM_STREAMS is not set
UCLIBC_HAS_PRINTF_M_SPEC=y
UCLIBC_HAS_ERRNO_MESSAGES=y
# UCLIBC_HAS_SYS_ERRLIST is not set
UCLIBC_HAS_SIGNUM_MESSAGES=y
# UCLIBC_HAS_SYS_SIGLIST is not set
UCLIBC_HAS_GNU_GETOPT=y
UCLIBC_HAS_GNU_GETSUBOPT=y

#
# Big and Tall
#
UCLIBC_HAS_REGEX=y
UCLIBC_HAS_REGEX_OLD=y
UCLIBC_HAS_FNMATCH=y
UCLIBC_HAS_FNMATCH_OLD=y
UCLIBC_HAS_WORDEXP=y
# UCLIBC_HAS_FTW is not set
UCLIBC_HAS_GLOB=y
UCLIBC_HAS_GNU_GLOB=y

#
# Library Installation Options
#
SHARED_LIB_LOADER_PREFIX="$(RUNTIME_PREFIX)lib"
RUNTIME_PREFIX="/usr/$(TARGET_ARCH)-linux-uclibc/"
DEVEL_PREFIX="/usr/$(TARGET_ARCH)-linux-uclibc/usr/"

#
# Security options
#
# UCLIBC_BUILD_PIE is not set
# UCLIBC_HAS_ARC4RANDOM is not set
# HAVE_NO_SSP is not set
# UCLIBC_HAS_SSP is not set
UCLIBC_BUILD_RELRO=y
# UCLIBC_BUILD_NOW is not set
UCLIBC_BUILD_NOEXECSTACK=y

#
# uClibc development/debugging options
#
CROSS_COMPILER_PREFIX=""
UCLIBC_EXTRA_CFLAGS=""
# DODEBUG is not set
# DODEBUG_PT is not set
# DOSTRIP is not set
# DOASSERTS is not set
# SUPPORT_LD_DEBUG is not set
# SUPPORT_LD_DEBUG_EARLY is not set
# UCLIBC_MALLOC_DEBUGGING is not set
WARNINGS="-Wall -pipe"
# EXTRA_WARNINGS is not set
# DOMULTI is not set
# UCLIBC_MJN3_ONLY is not set