Detailed backtrace:

#0  GetScreenPrime (master=0x7f1e37f39e20, master@entry=0x1,
prime_id=prime_id@entry=1) at ../../../../hw/xfree86/dri2/dri2.c:158
#1  0x00007f1e36f9a47d in GetScreenPrime (prime_id=prime_id@entry=1,
master=master@entry=0x1) at ../../../../hw/xfree86/dri2/dri2.c:151
#2  DRI2GetScreenPrime (master=<optimized out>, prime_id=prime_id@entry=1) at
../../../../hw/xfree86/dri2/dri2.c:169
#3  0x00007f1e36f9c447 in DRI2Connect (client=client@entry=0x7f1e38854de0,
pScreen=<optimized out>, driverType=65536, 
    fd=fd@entry=0x7fff2ef0bb70, driverName=driverName@entry=0x7fff2ef0bb80,
deviceName=deviceName@entry=0x7fff2ef0bb88)
    at ../../../../hw/xfree86/dri2/dri2.c:1312
#4  0x00007f1e36f9d09c in ProcDRI2Connect (client=0x7f1e38854de0) at
../../../../hw/xfree86/dri2/dri2ext.c:122
#5  ProcDRI2Dispatch (client=0x7f1e38854de0) at
../../../../hw/xfree86/dri2/dri2ext.c:596
#6  0x00007f1e36e7786e in Dispatch () at ../../dix/dispatch.c:433
#7  0x00007f1e36e7b68a in dix_main (argc=10, argv=0x7fff2ef0bd98,
envp=<optimized out>) at ../../dix/main.c:294
#8  0x00007f1e34718b45 in __libc_start_main () from
/lib/x86_64-linux-gnu/libc.so.6
#9  0x00007f1e36e66c2e in _start ()