Output from gdb backtrace full (after running 
gdb claws-mail then run --debug as found here: http://www.claws-mail.org/faq/index.php/Debugging_Claws

Prior to running that, when I ran 'run --debug' this showed up in the terminal where it normally would have crashed; and I saw on the bottom of the claws-mail screen where it shows status messages that it was running bogofilter filtering bodies, then it showed bogofilter filtering messages:

Program received signal SIGSEGV, Segmentation fault.
g_str_hash (v=0x0) at /tmp/buildd/glib2.0-2.32.3/./glib/ghash.c:1730
1730	/tmp/buildd/glib2.0-2.32.3/./glib/ghash.c: No such file or directory.


(gdb) backtrace full
#0  g_str_hash (v=0x0) at /tmp/buildd/glib2.0-2.32.3/./glib/ghash.c:1730
        p = 0x0
        h = 5381
#1  0x00007ffff4f094e9 in g_hash_table_lookup_node (
    hash_return=<synthetic pointer>, key=0x0, hash_table=0x9ccd20)
    at /tmp/buildd/glib2.0-2.32.3/./glib/ghash.c:401
        node_hash = <optimized out>
        hash_value = <optimized out>
        have_tombstone = 0
        step = 0
        node_index = <optimized out>
        first_tombstone = 0
#2  g_hash_table_lookup (hash_table=0x9ccd20, key=0x0)
    at /tmp/buildd/glib2.0-2.32.3/./glib/ghash.c:1074
        node_hash = <optimized out>
        __PRETTY_FUNCTION__ = "g_hash_table_lookup"
#3  0x0000000000458138 in addrcache_hash_add_email (email=0xa35080, 
    cache=<optimized out>) at addrcache.c:357
No locals.
#4  addrcache_person_add_email (cache=0xa35030, person=person@entry=0xdf6700, 
    email=email@entry=0xa35080) at addrcache.c:477
        retVal = 0
#5  0x0000000000587972 in addrbook_parse_address (person=0xdf6700, 
---Type <return> to continue, or q <return> to quit---
    file=0xbf8d30, book=<optimized out>) at addrbook.c:384
        value = <optimized out>
        attr = 0x0
        name = <optimized out>
        email = 0xa35080
#6  addrbook_parse_addr_list (book=book@entry=0xa34f20, 
    file=file@entry=0xbf8d30, person=person@entry=0xdf6700) at addrbook.c:414
        prev_level = <optimized out>
#7  0x0000000000589491 in addrbook_parse_person (file=0xbf8d30, book=0xa34f20)
    at addrbook.c:521
        attr = 0x0
        name = <optimized out>
        value = <optimized out>
        person = <optimized out>
#8  addrbook_read_tree (file=0xbf8d30, book=0xa34f20) at addrbook.c:778
        attr = <optimized out>
        name = <optimized out>
        value = <optimized out>
#9  addrbook_read_data (book=0xa34f20) at addrbook.c:944
        file = 0xbf8d30
        fileSpec = 0xdea8f0 "cn"
#10 0x000000000059869c in addrindex_ds_read_data (ds=0xa34c10)
    at addrindex.c:2443
---Type <return> to continue, or q <return> to quit---
        retVal = 0
        iface = <optimized out>
#11 addrindex_load_completion_load_persons (
    callBackFunc=callBackFunc@entry=0x45b4d0 <add_address>, ds=0xa34c10)
    at addrindex.c:2857
        nodeP = <optimized out>
        nodeM = <optimized out>
        sName = <optimized out>
#12 0x000000000059c58b in addrindex_load_completion (
    callBackFunc=callBackFunc@entry=0x45b4d0 <add_address>, 
    folderpath=folderpath@entry=0x0) at addrindex.c:3011
        iface = <optimized out>
        nodeIf = 0xa4a940
        nodeDS = 0xa4a6e0
#13 0x000000000045b3bb in read_address_book (folderpath=0x0)
    at addr_compl.c:296
No locals.
#14 0x000000000045b7a2 in start_address_completion (
    folderpath=folderpath@entry=0x0) at addr_compl.c:372
        different_book = 1
#15 0x00007fffd9a97764 in bogofilter_do_filter (data=0x9c43d0)
    at bogofilter.c:227
        ab_folderpath = 0x0
---Type <return> to continue, or q <return> to quit---
        bogo_pid = <optimized out>
        bogo_stdin = <optimized out>
        bogo_stdout = <optimized out>
        error = 0x0
        bogo_forked = <optimized out>
        status = 0
        msginfo = <optimized out>
        cur = 0x0
        total = 125
        curnum = 0
        file = 0x0
        buf = "\026", '\000' <repeats 16 times>"\266, \325\000\000\000\000\000\001\000\000\000\000\000\000\000(\000\000\000\000\000\000\000iU\365\364\377\177\000\000\000\266\325\000\000\000\000\000D8\363\364\377\177\000\000`$\274\000\000\000\000\000Pj\272\000\000\000\000\000p\213\325\000\000\000\000\000\231\303\035\365\377\177\000\000`$\274\000\000\000\000\000M`\346\362\377\177\000\000\000b\004\000\000\000\000\000\000>\351\000\000\000\000\000!\000\000\000\000\000\000\000`\376l\364\377\177\000\000`\376l\364\377\177\000\000Bo<\364\377\177\000\000\060\000\000\000\000\000\000\000!\000\000\000\000\000\000\000\021\231\233\000\000\000\000\000 -\235\000\000\000\000\000p\r\204\000\000\000\000\000\000\307\344\000\000\000\000\000\020\000\000\000\000\000\000\000\071\356\361\364\377\177\000\000!\000\000\000\000\000\000\000\274\315U\366\377\177\000\000\020\270\344\000\000\000\000\000 \004\004\000\377\177"...
---Type <return> to continue, or q <return> to quit---
#16 0x00007fffd9a985b9 in mail_filtering_hook (source=0x7fffffffccc0, 
    data=<optimized out>) at bogofilter.c:528
        mail_filtering_data = 0x7fffffffccc0
        msginfo = <optimized out>
        msglist = 0xde12a0
        cur = <optimized out>
        warned_error = 0
        status = 0
        total = 125
        curnum = <optimized out>
        new_hams = 0x0
        new_spams = 0x0
        new_unsure = <optimized out>
        whitelisted_new_spams = 0x0
        bogo_exec = <optimized out>
        bogo_args = {0x7fffe0013370 "bogofilter", 0x7fffd9a9a826 "-T", 
          0x7fffd9a9a73f "-b", 0x0}
        ok_to_thread = <optimized out>
#17 0x00000000005d2a8c in hooks_marshal (data=0x7fffffffbc80, 
    hook=<optimized out>) at hooks.c:107
        func = <optimized out>
#18 hooks_marshal (hook=<optimized out>, data=0x7fffffffbc80) at hooks.c:100
        marshal_data = 0x7fffffffbc80
---Type <return> to continue, or q <return> to quit---
#19 0x00007ffff4f0ad34 in g_hook_list_marshal (hook_list=0x7fffe0012360, 
    may_recurse=may_recurse@entry=1, 
    marshaller=marshaller@entry=0x5d2a70 <hooks_marshal>, 
    data=data@entry=0x7fffffffbc80)
    at /tmp/buildd/glib2.0-2.32.3/./glib/ghook.c:676
        was_in_call = 0
        hook = 0xdceb80
        __PRETTY_FUNCTION__ = "g_hook_list_marshal"
#20 0x00000000005d30f4 in hooks_invoke (
    hooklist_name=hooklist_name@entry=0x666d98 "mail_listfiltering_hooklist", 
    source=source@entry=0x7fffffffccc0) at hooks.c:125
        hooklist = <optimized out>
        marshal_data = {source = 0x7fffffffccc0, abort = 0}
#21 0x0000000000548d8e in procmsg_msglist_filter (list=list@entry=0xde12a0, 
    ac=0xd3d2b0, filtered=filtered@entry=0x7fffffffdd80, 
    unfiltered=unfiltered@entry=0x7fffffffdd88, do_filter=1) at procmsg.c:2331
        cur = <optimized out>
        to_do = 0x0
        total = 125
        curnum = 0
        mail_filtering_data = {msginfo = 0x0, msglist = 0xde12a0, 
          filtered = 0x0, unfiltered = 0x0, account = 0xd3d2b0}
#22 0x00000000004b694e in inc_start (inc_dialog=inc_dialog@entry=0x9d7200)
---Type <return> to continue, or q <return> to quit---
    at inc.c:707
        filtered = 0x0
        unfiltered = 0x0
        session = 0x9a47e0
        qlist = <optimized out>
        pop3_session = 0x9d3290
        inc_state = INC_SUCCESS
        error_num = <optimized out>
        new_msgs = <optimized out>
        msg = <optimized out>
        fin_msg = <optimized out>
        processing = 0x9b7730
        inbox = 0xd89590
        msglist = 0xde12a0
        msglist_element = <optimized out>
        cancelled = 0
#23 0x00000000004b7b09 in inc_all_account_mail (mainwin=0xa71270, autocheck=1, 
    notify=0) at inc.c:404
        list = <optimized out>
        queue_list = 0xd78300
        inc_dialog = 0x9d7200
        new_msgs = 0
        account_new_msgs = <optimized out>
---Type <return> to continue, or q <return> to quit---
#24 0x00000000004b8ad8 in defer_check_all (
    data=<error reading variable: value has been optimized out>) at main.c:376
        autochk = <error reading variable autochk (value has been optimized out)>
#25 0x00007ffff4f19d9b in g_timeout_dispatch (source=source@entry=0xd44eb0, 
    callback=<optimized out>, user_data=<optimized out>)
    at /tmp/buildd/glib2.0-2.32.3/./glib/gmain.c:3882
        timeout_source = <optimized out>
        again = <optimized out>
#26 0x00007ffff4f19205 in g_main_dispatch (context=0xa1e340)
    at /tmp/buildd/glib2.0-2.32.3/./glib/gmain.c:2539
        dispatch = 0x7ffff4f19d80 <g_timeout_dispatch>
        was_in_call = 0
        user_data = 0x1
        callback = 0x4b8ac0 <defer_check_all>
        cb_funcs = 0x7ffff51c4980
        cb_data = 0x9f83d0
        current_source_link = {data = 0xd44eb0, next = 0x0}
        need_destroy = <optimized out>
        source = 0xd44eb0
        current = 0xdcb0a0
        i = <optimized out>
#27 g_main_context_dispatch (context=context@entry=0xa1e340)
---Type <return> to continue, or q <return> to quit---
    at /tmp/buildd/glib2.0-2.32.3/./glib/gmain.c:3075
No locals.
#28 0x00007ffff4f19538 in g_main_context_iterate (context=0xa1e340, 
    block=block@entry=1, dispatch=dispatch@entry=1, 
    self=<error reading variable: Unhandled dwarf expression opcode 0xfa>)
    at /tmp/buildd/glib2.0-2.32.3/./glib/gmain.c:3146
        max_priority = 2147483647
        timeout = 474
        some_ready = 1
        nfds = <optimized out>
        allocated_nfds = <optimized out>
        fds = 0x9abc00
#29 0x00007ffff4f19932 in g_main_loop_run (loop=0x9ddc60)
    at /tmp/buildd/glib2.0-2.32.3/./glib/gmain.c:3340
        __PRETTY_FUNCTION__ = "g_main_loop_run"
#30 0x00007ffff7292a77 in gtk_main ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
No symbol table info available.
#31 0x000000000044d320 in main (argc=1, argv=0x7fffffffe448) at main.c:1686
        connection = 0xa20d78
        error = 0x0
        nm_proxy = 0xa12310
        userrc = <optimized out>
---Type <return> to continue, or q <return> to quit---
        mainwin = 0xa71270
        folderview = 0xbc2800
        icon = 0xa65b20
        crash_file_present = <optimized out>
        num_folder_class = <optimized out>
        asked_for_migration = <optimized out>
        start_done = <optimized out>
        gui_manager = <optimized out>
        plug_list = 0x0
        never_ran = <optimized out>
        start = {tv_sec = 1344038854, tv_usec = 43817}
        end = {tv_sec = 1344038856, tv_usec = 84755}
        diff = {tv_sec = 2, tv_usec = 40938}
        timing_name = 0x65c575 "startup"
        __FUNCTION__ = "main"
(gdb) 
(gdb) 

