[ I've raised this against 4.2 as I've verified that it's still an issue for
that branch, but it's also valid for 4.0.2 & 4.1 ]
I have a crash in some code that dlopen()s a library (with a static <deque>
constructor), which happens to be dependant upon another couple of libraries,
one of which uses libpthread.
The crash occurs in the static library construction mt_allocator.h, within
_M_adjust_freelist:
void
_M_adjust_freelist(const _Bin_record& __bin, _Block_record* __block,
size_t __thread_id)
{
if (__gthread_active_p())
{
__block->_M_thread_id = __thread_id;
HERE -> --__bin._M_free[__thread_id];
++__bin._M_used[__thread_id];
}
}
At the point at which it happens, _M_free is NULL.
I've done some investigation, and the mal-initialisation is caused by
__gthread_active_p() sometimes returning '1' [e.g.,in mt_allocator.h's
__pool<true>::_M_initialize_once()] and '0':
__common_pool_base<_PoolTp,true>::_S_initialize_once() calls this
_M_initialise_once() [if I'm right], which runs down to mt_allocator.cc's
__pool<true>::_M_initialize(). At this point, __gthread_active_p() returns
/0/, (even though it's only just previously returned 1) and the routine doesn't
seem to quite know how to handle it, leaving the bin(s) uninitialised.
I found this problem using Fedora Core's 4.0.1/4.0.2 but have replicated it
with vanilla builds with mt_allocator enabled. This *may* be a dup. of PR
24071; I'm not sure it's exactly the same, but I feel we may be circling round
the same issue.
Redhat's https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=165728 may also
be relevant.
I'm fairly confident that the GLIBCXX_FORCE_NEW env. var. makes things work
properly. I've also found that, instead, the semi-documented '-pthread'
compilation [from the above PR] option makes things work OK too
[semi-documented as it's listed as being PPC/Sparc/HP-UX specific, whereas this
is a basic 32-bit i686 system].
The last thing I tried which *also* made things work on its own (ref,. the
RedHat report) was to link my test util. (the one that does the dlopen()) with
'-lpthread'.
--
Summary: STL mt_allocator crash in global construcutor
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: neil at fnxweb dot com
GCC build triplet: i386-redhat-linux
GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25409
