I get:
[ 7473.976353] show_signal_msg: 1 callbacks suppressed
[ 7473.976355] VKRenderThread[20914]: segfault at 13 ip 00007fc2e58efd71 sp 00007fc2d756dd50 error 4 in libX11.so.6.3.0[7fc2e5878000+133000]
[ 7473.976362] Code: 49 89 c4 0f 84 b0 01 00 00 8b 44 24 38 8d 68 ff 85 c0 89 6c 24 38 7e 2b 49 8b 45 18 4c 89 e7 83 ed 01 48 83 c3 08 49 83 c5 50 <48> 8b 30 e8 47 59 fa ff 83 fd ff 4c 89 63 f8 89 6c 24 38 4c 8d 60
[ 7474.036165] VKRenderThread[20912]: segfault at 0 ip 00007fc2e22dc5ea sp 00007fc2d7572730 error 6 in libtier0.so[7fc2e22a0000+8c000]
[ 7474.036174] Code: 85 c9 7e 26 31 db 48 63 c3 49 8b 74 c4 08 48 85 f6 74 0e 48 8d 3d 58 48 03 00 31 c0 e8 ef 14 fe ff 83 c3 01 41 39 1c 24 7f dc <c7> 04 25 00 00 00 00 ef be ad de 5b 41 5c 5d c3 66 0f 1f 44 00 00

hw: amd tahiti xt
last known working commit:c3325097be93d6374a6b5f9fb5eee0878698ef77
crashing commit:de57926dc909b3fb180ff06a6c5235309fdbf4df
roughly 1 week
(linux/drm/xserver git from today)