Program received signal SIGSEGV, Segmentation fault.
__GI___libc_free (mem=0x80) at malloc.c:2951
2951    malloc.c: No such file or directory.
(gdb) bt f
#0  __GI___libc_free (mem=0x80) at malloc.c:2951
        ar_ptr = <optimized out>
        p = <optimized out>
        hook = 0x0
#1  0x00005581c1673d84 in xi2mask_free (mask=mask@entry=0x5581c43e10c0) at ../../dix/inpututils.c:1085
No locals.
#2  0x00005581c1670dd4 in FreeGrab (pGrab=0x5581c43e1050) at ../../dix/grabs.c:263
No locals.
#3  0x00005581c174eb32 in ProcXIUngrabDevice (client=0x5581c3f7cb00) at ../../Xi/xigrabdev.c:169
        dev = 0x5581c39a2d10
        grab = 0x5581c43e1050
        ret = 0
        time = <optimized out>
        stuff = <optimized out>
#4  0x00005581c1656d9f in Dispatch () at ../../dix/dispatch.c:430
        clientReady = 0x5581c3c47ed0
        result = <optimized out>
        client = 0x5581c3f7cb00
        nready = 0
        icheck = 0x5581c1a57130 <checkForInput>
        start_tick = 230
#5  0x00005581c165ae13 in dix_main (argc=11, argv=0x7fff5c71e9d8, envp=<optimized out>) at ../../dix/main.c:300
        i = <optimized out>
        alwaysCheckForInput = {0, 1}
#6  0x00007f7b89565830 in __libc_start_main (main=0x5581c1645030 <main>, argc=11, argv=0x7fff5c71e9d8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff5c71e9c8) at ../csu/libc-start.c:291
        result = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {0, 3838367663484396932, 94015783718976, 140734744357328, 0, 0, 7041841011566667140, 6967085495363134852}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0xb, 0x5581c1645030 <main>}, data = {prev = 0x0, cleanup = 0x0, 
              canceltype = 11}}}
        not_first_call = <optimized out>
#7  0x00005581c1645069 in _start ()