segmentation fault in amdgpu-pro when starting xorg

Using the amdgpu-pro 17.30 drivers for an RX 570 running on Ubuntu 16.04.3, I'm unable to start X

[    13.002] (EE) Backtrace:

[    13.002] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x6d4bdf5bce]

[    13.002] (EE) 1: /usr/lib/xorg/Xorg (0x6d4bc43000+0x1b6f59) [0x6d4bdf9f59]

[    13.002] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7fbc51e99000+0x354b0) [0x7fbc51ece4b0]

[    13.002] (EE) 3: /opt/amdgpu-pro/lib/xorg/modules/libglamoregl.so (glamor_init+0x168) [0x7fbc4f5e4338]

[    13.002] (EE) 4: /usr/lib/xorg/modules/drivers/modesetting_drv.so (0x7fbc4fe21000+0x7860) [0x7fbc4fe28860]

[    13.002] (EE) 5: /usr/lib/xorg/Xorg (AddScreen+0x101) [0x6d4bc97111]

[    13.002] (EE) 6: /usr/lib/xorg/Xorg (InitOutput+0x3f1) [0x6d4bcdb851]

[    13.002] (EE) 7: /usr/lib/xorg/Xorg (0x6d4bc43000+0x57c04) [0x6d4bc9ac04]

[    13.002] (EE) 8: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7fbc51eb9830]

[    13.002] (EE) 9: /usr/lib/xorg/Xorg (_start+0x29) [0x6d4bc85069]

[    13.002] (EE)

[    13.002] (EE) Segmentation fault at address 0x6d4bde38b0

[    13.002] (EE)

Fatal server error:

[    13.002] (EE) Caught signal 11 (Segmentation fault). Server aborting

This is with a clean install and up-to-date 16.04.3, following the instructions from - AMDGPU-PRO Driver for Linux Release Notes

Not quite sure if I've messed something up, or whether this is a software issue in the drivers?