.
Thread 2 (LWP 22789):
#0  0x00007f031e21a3cd in poll () at ../sysdeps/unix/syscall-template.S:81
No locals.
#1  0x00007f031f54015c in g_main_context_poll (n_fds=1, fds=0x7f03040008c0, timeout=-1, context=0x19dbb30, priority=<optimized out>) at /build/buildd/glib2.0-2.35.8/./glib/gmain.c:3995
        poll_func = 0x7f031f54e550 <g_poll>
#2  g_main_context_iterate (context=context@entry=0x19dbb30, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.35.8/./glib/gmain.c:3696
        max_priority = 2147483647
        timeout = -1
        some_ready = <optimized out>
        allocated_nfds = <optimized out>
        fds = 0x7f03040008c0
        nfds = 1
#3  0x00007f031f540284 in g_main_context_iteration (context=0x19dbb30, may_block=may_block@entry=1) at /build/buildd/glib2.0-2.35.8/./glib/gmain.c:3762
        retval = <optimized out>
#4  0x00007f031f5402e1 in glib_worker_main (data=<optimized out>) at /build/buildd/glib2.0-2.35.8/./glib/gmain.c:5427
No locals.
#5  0x00007f031f564075 in g_thread_proxy (data=0x330e990) at /build/buildd/glib2.0-2.35.8/./glib/gthread.c:798
        thread = 0x330e990
#6  0x00007f031f03ff8e in start_thread (arg=0x7f030bf8d700) at pthread_create.c:311
        __res = <optimized out>
        pd = 0x7f030bf8d700
        now = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {139651062486784, -2733192428335920933, 0, 139651417911392, 140734112245600, 4096, 2600732054461090011, 2600690178979662043}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = 0
        pagesize_m1 = <optimized out>
        sp = <optimized out>
        freesize = <optimized out>
        __PRETTY_FUNCTION__ = "start_thread"
#7  0x00007f031e226e1d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113
No locals.
.
Thread 1 (LWP 22125):
#0  ~basic_string (this=0x7fff36c4b210, __in_chrg=<optimized out>) at /usr/include/c++/4.7/bits/basic_string.h:536
No locals.
#1  pkgProblemResolver::DoUpgrade (this=0x7fff36c4b240, Pkg=...) at algorithms.cc:730
        P = {<pkgCache::Iterator<pkgCache::Package, pkgCache::PkgIterator>> = {<std::iterator<std::forward_iterator_tag, pkgCache::Package, long, pkgCache::Package*, pkgCache::Package&>> = {<No data fields>}, _vptr.Iterator = 0x1e89c78, S = 0x2a26fb8, Owner = 0x1b1b0a8}, HashIndex = 0}
        Start = {<pkgCache::Iterator<pkgCache::Dependency, pkgCache::DepIterator>> = {<std::iterator<std::forward_iterator_tag, pkgCache::Dependency, long, pkgCache::Dependency*, pkgCache::Dependency&>> = {<No data fields>}, _vptr.Iterator = 0x319, S = 0x4, Owner = 0x7fff36c4b2af}, Type = (unknown: 918860936)}
        End = {<pkgCache::Iterator<pkgCache::Dependency, pkgCache::DepIterator>> = {<std::iterator<std::forward_iterator_tag, pkgCache::Dependency, long, pkgCache::Dependency*, pkgCache::Dependency&>> = {<No data fields>}, _vptr.Iterator = 0x6102c6f020, S = 0x1074188, Owner = 0x6b1d58}, Type = (unknown: 14316704)}
        D = {<pkgCache::Iterator<pkgCache::Dependency, pkgCache::DepIterator>> = {<std::iterator<std::forward_iterator_tag, pkgCache::Dependency, long, pkgCache::Dependency*, pkgCache::Dependency&>> = {<No data fields>}, _vptr.Iterator = 0x1b1b090, S = 0x1c95d50, Owner = 0xeda880}, Type = (unknown: 4466924)}
        group = {cache = @0x27a6e70, released = 128}
        WasKept = false
        Fail = <optimized out>
#2  0x00007f031e1b0580 in __GI___libc_malloc (bytes=18321984) at malloc.c:2859
        ar_ptr = 0x0
        victim = 0x27a6e70
        __func__ = "__libc_malloc"
#3  0x00000000018f7480 in ?? ()
No symbol table info available.
#4  0x0000000000db9b40 in ?? ()
No symbol table info available.
#5  0x0000000000000000 in ?? ()
No symbol table info available.