Xorg segfault on cpu which does not support PAT
Submitted by Snir Sheriber
Assigned to Intel 3D Bugs Mailing List
Created attachment 144351 gdb bt
My setup is as follow:
OS: fedora 30 5.0.11-300 cpu: QEMU Virtual CPU 2.5+ (without PAT - qemu's default) gpu: assigned vGPU using GVTg mesa-dri-drivers: 19.0.3-1 xorg-x11-server-Xorg: 1.20.4-3
(This is a vm running on top of fedora 30 host, same kernel with Intel i7-6600u)
When i'm running inside xorg session and trying to open firefox, xorg crashes. bisecting points to this patch: 54c823ec (mesa)
It seems that in case cpu does not support PAT, mapping may fail (brw_bo_map_wc fails without PAT and won't fallback since MAP_RAW is set) so that intel_miptree_map_raw will use *dst when it's NULL, passing it to linear_to_tiled which is trying to access *dst(=NULL).
Backtrace is attached.
Attachment 144351, "gdb bt":