List of classes of commands:

aliases -- Aliases of other commands
breakpoints -- Making program stop at certain points
data -- Examining data
files -- Specifying and examining files
internals -- Maintenance commands
obscure -- Obscure features
running -- Running the program
stack -- Examining the stack
status -- Status inquiries
support -- Support facilities
tracepoints -- Tracing of program execution without stopping the program
user-defined -- User-defined commands

Type "help" followed by a class name for a list of commands in that class.
Type "help all" for the list of all commands.
Type "help" followed by command name for full documentation.
Type "apropos word" to search for commands related to "word".
Command name abbreviations are allowed if unambiguous.
Undefined command: "running".  Try "help".
The program being debugged has been started already.
Start it from the beginning? (y or n) Program not restarted.
Continuing.

Program received signal SIGUSR1, User defined signal 1.
0x00007fe5b539f6e3 in select () from /lib/x86_64-linux-gnu/libc.so.6
Detaching from program: /usr/bin/Xorg, process 949
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x00007fb8c2c0893f in glamor_poly_segment_solid_gl (drawable=0x7fb8c7544010, 
    gc=0x7fb8c98de36a, nseg=20, 
    segs=0x7fb8c98de2c4)
    at ../../glamor/glamor_segs.c:80
warning: Source file is more recent than executable.
80	            v[j++] = segs[i];
Detaching from program: /usr/bin/Xorg, process 1238
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x00007f79419c5a7f in glamor_poly_segment_solid_gl (drawable=0x7f7945ec2010, 
    gc=0x5619d965dbd2, nseg=1, 
    segs=0x5619d965dbc4)
    at ../../glamor/glamor_segs.c:80
80	            v[j++] = segs[i];
#0  0x00007f79419c5a7f in glamor_poly_segment_solid_gl (
    drawable=0x7f7945ec2010, 
    gc=0x5619d965dbd2, nseg=1, 
    segs=0x5619d965dbc4)
    at ../../glamor/glamor_segs.c:80
        screen = 0x5619d91d27b0
        pixmap = 0x5619d965dbd2
        off_x = -644167256
        off_y = 22041
        v = 0x7f7938ac1e58
        vbo_offset = 0x43e58 <error: Cannot access memory at address 0x43e58>
        box_x = 1103026689
#1  0x00007f79419c5e18 in glamor_poly_segment_gl (segs=0x5619d965dbc4, nseg=1, 
    gc=0x5619d99ac900, 
    drawable=0x5619d9936480)
    at ../../glamor/glamor_segs.c:129
No locals.
#2  glamor_poly_segment (
    drawable=0x5619d9936480, 
    gc=0x5619d99ac900, nseg=1, 
    segs=0x5619d965dbc4)
    at ../../glamor/glamor_segs.c:164
No locals.
#3  0x00005619d7d2b704 in damagePolySegment (pDrawable=0x5619d9936480, 
    pGC=0x5619d99ac900, nSeg=1, 
    pSeg=<optimized out>)
    at ../../../miext/damage/damage.c:992
        oldFuncs = 0x5619d80336a0 <damageGCFuncs>
#4  0x00005619d7c3f2e6 in ProcPolySegment (client=0x5619d9718890)
    at ../../dix/dispatch.c:1790
        nsegs = <optimized out>
        pGC = 0x5619d99ac900
        pDraw = 0x5619d9936480
        stuff = 0x5619d965dbb8
#5  0x00005619d7c42d8f in Dispatch ()
    at ../../dix/dispatch.c:429
        clientReady = 0x5619d946e750
        result = <optimized out>
        client = 0x5619d9718890
        nready = 0
        icheck = 0x5619d803dd70 <checkForInput>
        start_tick = 485
#6  0x00005619d7c46e7b in dix_main (
    argc=15, argv=0x7ffefa4fd098, 
    envp=<optimized out>)
    at ../../dix/main.c:298
        i = <optimized out>
        alwaysCheckForInput = {0, 1}
#7  0x00007f7943880850 in __libc_start_main ()
   from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#8  0x00005619d7c31329 in _start ()
No symbol table info available.
Detaching from program: /usr/bin/Xorg, process 1978