(gdb) bt full
#0  0x080838f0 in pbx_substitute_variables_helper_full (c=0x0, headp=0x3c8, cp1=0x819f717 "${GROUP_SUPPORT}&SIP/128", cp2=0xbfa2dbb0 "", count=255)
    at strings.h:151
        cp4 = 0xb7d599f4 "\201\uffff"
        whereweare = 0x819f727 "&SIP/128"
        length = 135919385
        workspace = 0x819a8a0 "general"
        ltmp = 0x805d1bc "\205\uffffu\a\213SP\205\ufffft\032\213[\\\205\uffffu\uffff1\uffff\211\uffff1\uffff\205\ufffft\003\213BT\203\uffff\024[^\uffff\211\uffff\uffff\uffff\213KP\205\uffffu\uffff\uffff\uffff\211\uffffUWVS\203\uffff\f\213t$$\213l$ \213|$(\205\uffffta\211t$\004\211,$\uffffM\uffff\uffff\uffff\205\uffff\211\ufffft\022\215\uffff&"
        var = 0x37 <Address 0x37 out of bounds>
        nextvar = 0xd <Address 0xd out of bounds>
        nextexp = 0x0
        vars = 0x819f719 "GROUP_SUPPORT}&SIP/128"
        vare = 0x37 <Address 0x37 out of bounds>
        pos = 55
        brackets = 14
        needsub = 0
        len = 13
#1  0x08083d11 in pbx_substitute_variables_helper (c=0xe, cp1=0x47 <Address 0x47 out of bounds>, cp2=0x47 <Address 0x47 out of bounds>, count=71)
    at pbx.c:1560
No locals.
#2  0xb78a1f23 in pbx_load_module () at pbx_config.c:1632
        cfg = (struct ast_config *) 0x8199908
        v = (struct ast_variable *) 0x819f6e0
        cxt = 0x0
        pri = 0x81997a0 "\uffffx\026\b\003"
        appl = 0xbfa2dcb0 "\uffffT\uffff\uffff\001"
        data = 0xbfa2daf0 "\uffff\uffff\uffff\uffff\uffff\uffff\uffff\uffff"
        tc = 0x0
        cidmatch = 0x78c3574 <Address 0x78c3574 out of bounds>
        con = (struct ast_context *) 0x80fbe33
        label = 0xb7f22875 "\205\uffff\211\uffff\177\021\017\214\uffff\002"
        realvalue = '\0' <repeats 255 times>
        lastpri = -2
#3  0xb789f0c7 in load_module () at pbx_config.c:1791
No locals.
#4  0x0805bcf3 in __load_resource (resource_name=0x815b70b "pbx_config.so", cfg=0x21) at loader.c:413
        fn = "/usr/lib/asterisk/modules/pbx_config.so\000so\000o", '\0' <repeats 211 times>
        errors = 0
        res = 71
        m = (struct module *) 0x8199520
        flags = -1079845232
        val = 0x47 <Address 0x47 out of bounds>
        key = (unsigned char *) 0xbfa2de90 "Text Extension Configuration"
        tmp = "Text Extension Configuration\000+\uffff\uffff\001\000\000\000\uffffT\uffff\uffff\020b\uffff\uffff\000\000\000\000\uffff_\uffff\uffff\000\000\000\000\000\000\000\000b*\uffff\uffff\uffff\uffff\uffff\uffff\000\000\000\000 h\uffff\uffff\000~\uffff\uffff"
#5  0x0805b4cb in load_modules (preload_only=-1079845072) at loader.c:553
        mods = (DIR *) 0x815b428
        d = (struct dirent *) 0xbfa2df30
        x = 2
        cfg = (struct ast_config *) 0x812bc50
        v = (struct ast_variable *) 0x812bc50
        tmp = "pbx_config.so\000so\000o\000\000\000\000\000\000\000\000\000\000\001\000\000\000\uffff(\021\b\000\000\000\000\b\uffff\uffff\uffffT\005\000\000\uffff\"\021\b\037\000\000\000\b\uffff\uffff\uffff \uffff\b\b\uffff\"\021\bp\222\b\b`m\017\b\uffffm\017\b"
#6  0x080b3613 in main (argc=-1079844464, argv=0xbfa2e354) at asterisk.c:2158
        pw = (struct passwd *) 0x1
        c = 71
        filename = "/root/.asterisk_history", '\0' <repeats 56 times>
        hostname = "pbx", '\0' <repeats 60 times>
        tmp = "\uffff\uffff\uffff\uffff\uffffy\uffff\uffff\uffff+\uffff\uffff\032\000\000\000\uffffT\uffff\uffffp\213\uffff\uffff\000\000\000\000\uffffy\uffff\uffff\uffffy\uffff\uffff\uffffy\uffff\uffff\uffffc\uffff\uffff\uffff\uffff\uffff\uffff\uffffy\uffff\uffffHE\022\b\022\207\uffff\uffff\uffffT\uffff\uffff\uffffy\uffff\uffffHE\022\b\uffff_\uffff\uffff\uffff\210\uffff\uffff"
        xarg = 0x0
        x = 14
        f = (FILE *) 0x1
        sigs = {__val = {134238211, 0 <repeats 31 times>}}
        num = 15
        is_child_of_nonroot = 5978
        buf = 0x1 <Address 0x1 out of bounds>
        runuser = 0x0
        rungroup = 0x0