On Friday 28 March 2008, Sverre Froyen wrote:
On Thursday 27 March 2008, Mark Davies wrote:
...
Moving forward we need to either identify what the actual ABI
change was and reverse it or bump the version number of the
library.
OK. I have a new libstdc++ built with -g and all my old binaries.
What can I do to help track this down?
Here's a backtrace example from artsd segfaulting:
Program received signal SIGSEGV, Segmentation fault.
0xbb606906 in std::ostream::flush (this=0xbb676620)
at
/usr/src/gnu/dist/gcc4/libstdc++-v3/include/bits/basic_ios.h:308
308 { return _M_streambuf; }
Current language: auto; currently c++
#0 0xbb606906 in std::ostream::flush (this=0xbb676620)
at
/usr/src/gnu/dist/gcc4/libstdc++-v3/include/bits/basic_ios.h:308
#1 0xbb623b56 in sentry (this=0xbfbfdbeb, __in=@0xbfbfdc58,
__noskip=false) at
/usr/src/gnu/dist/gcc4/libstdc++-v3/include/bits/istream.tcc:58
#2 0xbb642da5 in std::operator>><char, std::char_traits<char>,
std::allocator<char> > (__in=@0xbfbfdc58, __str=@0xbfbfdee0) at
/usr/src/gnu/dist/gcc4/libstdc++-v3/src/istream.cc:277 #3
0xbb91fe60 in Arts::MCOPConfig::readListEntry ()
from /usr/pkg/lib/libmcop.so.1
#4 0xbb917649 in readPath () from /usr/pkg/lib/libmcop.so.1
#5 0xbb9177c5 in Arts::MCOPUtils::traderPath ()
from /usr/pkg/lib/libmcop.so.1
#6 0xbb922676 in Arts::TraderHelper::load () from
/usr/pkg/lib/libmcop.so.1 #7 0xbb922730 in
Arts::TraderHelper::TraderHelper ()
from /usr/pkg/lib/libmcop.so.1
#8 0xbb922778 in Arts::TraderHelper::the () from
/usr/pkg/lib/libmcop.so.1 #9 0xbb9239c8 in
Arts::TraderQuery_impl::query ()
from /usr/pkg/lib/libmcop.so.1
#10 0x08062d9b in
Arts::SimpleSoundServer_impl::SimpleSoundServer_impl () #11
0x0805b416 in Arts::SoundServerV2_impl::SoundServerV2_impl () #12
0x0805d7b3 in SoundServerV2_impl_Factory::createInstance () #13
0xbb90f87d in Arts::ObjectManager::create ()
from /usr/pkg/lib/libmcop.so.1
#14 0xbbbb8ebc in Arts::SoundServerV2_base::_create ()
The segentaion fault happens because __in._M_tie is bogus (see
frame 1, above). Here's a dump of __in:
(gdb) print __in
$1 = (class std::basic_istream<char,std::char_traits<char> >
&) @0xbfbfdc58: {<std::basic_ios<char,std::char_traits<char>
= {<std::ios_base> = {_vptr.ios_base = 0xbb673360, static
boolalpha = std::_S_boolalpha,
static dec = std::_S_dec, static fixed = std::_S_fixed,
static hex = std::_S_hex, static internal = std::_S_internal,
static left = std::_S_left, static oct = std::_S_oct,
static right = std::_S_right, static scientific =
std::_S_scientific, static showbase = std::_S_showbase,
static showpoint = std::_S_showpoint, static showpos =
std::_S_showpos, static skipws = std::_S_skipws, static unitbuf =
std::_S_unitbuf, static uppercase = std::_S_uppercase,
static adjustfield = std::_S_adjustfield,
static basefield = std::_S_basefield,
static floatfield = std::_S_floatfield, static badbit =
std::_S_badbit, static eofbit = std::_S_eofbit, static failbit =
std::_S_failbit, static goodbit = std::_S_goodbit, static app =
std::_S_app, static ate = std::_S_ate, static binary = std::_S_bin,
static in = std::_S_in, static out = std::_S_out,
static trunc = std::_S_trunc, static beg = std::_S_beg,
static cur = std::_S_cur, static end = std::_S_end,
_M_precision = 134694080, _M_width = 6, _M_flags = 0,
_M_exception = 4098, _M_streambuf_state = std::_S_goodbit,
_M_callbacks = 0x0, _M_word_zero = {_M_pword = 0x0, _M_iword
= 0}, _M_local_word = {{_M_pword = 0x0, _M_iword = 0}, {_M_pword =
0x0, _M_iword = 0}, {_M_pword = 0x0, _M_iword = 0}, {_M_pword =
0x0, _M_iword = 0}, {_M_pword = 0x0, _M_iword = 0}, {_M_pword =
0x0, _M_iword = 0}, {_M_pword = 0x0, _M_iword = 0}, {_M_pword =
0x0, _M_iword = 0}}, _M_word_size = 0, _M_word = 0x8, _M_ios_locale
= { static none = 0, static ctype = 1, static numeric = 2, static
collate = 4, static time = 8, static monetary = 16, static messages
= 32, static all = 63, _M_impl = 0xbfbfde74, static _S_classic =
0xbb676620, static _S_global = 0xbb676620, static _S_categories =
0xbb671064, static _S_once = {pto_mutex = { ptm_magic = 858980355,
ptm_errorcheck = 0, ptm_recursed = 0, ptm_waiters = 0x0, ptm_owner
= 0x0}, pto_done = 1}}}, _M_tie = 0xbb676620, _M_fill = 0 '\0',
_M_fill_init = false, _M_streambuf = 0xbfbf0000, _M_ctype =
0xbfbfdc60, _M_num_put = 0xbb676760, _M_num_get = 0xbb6769a0},
_vptr.basic_istream = 0x80744ac, _M_gcount = 0}
Notice that the address 0xbb676620 is pointed to by _M_tie as well
as several other members. In fact, 0xbb676620 contains the global
variable __gnu_internal::c_locale_impl.
(gdb) print __in._M_tie
$2 = (class std::basic_ostream<char,std::char_traits<char> > *)
0xbb676620 (gdb) x 0xbb676620
0xbb676620 <_ZN14__gnu_internal13c_locale_implE>: 0x00000012
(std::ostream::flush attempts to use the 0x12 as an address causing
the violation)
I attemped to add a breakpoint at (all) the std::basic_istream
constructors in libstdc++, but either I missed one or it is never
called!?
Does this ring a bell with any one? Suggestions?
Thanks,
Sverre
PS I see some weirdness with gdb. stepi in most cases work like
continue and some times gdb places itself in the background (an fg
seems to restore it properly).