crash loops cosmic-comp when vkms is enabled

[Quackdoc]

I tried to enable vkms with cosmic and it crashed cosmic-comp and bootloops it, however this only happens when a window is drawn on the second screen. sending a mouse to it does not seem to cause issues.

vkms was enabled simply by doing sudo modprove vkms

journalctl --boot -e _EXE=/usr/bin/cosmic-session > /tmp/log.txt log.txt

full log truncated to when vkms is loaded is here log-full.txt

I did do some investigating and it seems like

interestingly below is the log for dmesg when this happens

[57572.492760] [drm] Initialized vkms 1.0.0 for vkms on minor 0
[57572.494639] platform vkms: [drm] fb1: vkmsdrmfb frame buffer device
[57577.099760] llvmpipe-1[170107]: segfault at 0 ip 0000726fa011c374 sp 0000726f47ffe3a0 error 4
[57577.099760] llvmpipe-9[170115]: segfault at 700 ip 0000726fa011c374 sp 0000726f2b60f400 error 4
[57577.099760] llvmpipe-3[170109]: segfault at 400 ip 0000726fa011c374 sp 0000726f3f36c400 error 4
[57577.099766] llvmpipe-5[170111]: segfault at 300 ip 0000726fa011c374 sp 0000726f3e36a400 error 4
[57577.099765] llvmpipe-7[170113]: segfault at 500 ip 0000726fa011c374 sp 0000726f3d368400 error 4
[57577.099771]  likely on CPU 7 (core 1, socket 0)
[57577.099770]  likely on CPU 11 (core 6, socket 0)
[57577.099771]  likely on CPU 0 (core 0, socket 0)
[57577.099771]  likely on CPU 1 (core 1, socket 0)
[57577.099771]  likely on CPU 9 (core 4, socket 0)
[57577.099769] llvmpipe-2[170108]: segfault at 2c100 ip 0000726fa011c374 sp 0000726f3fb6d3a0 error 4
[57577.099772] llvmpipe-0[170106]: segfault at 200 ip 0000726fa011c374 sp 0000726f73ffe400 error 4





[57577.099777] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57577.099778] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57577.099778] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57577.099779] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57577.099780] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57577.099780]  likely on CPU 4 (core 5, socket 0)
[57577.099784]  likely on CPU 8 (core 2, socket 0)
[57577.099786] llvmpipe-11[170117]: segfault at 600 ip 0000726fa011c374 sp 0000726f2a60d400 error 4

[57577.099789] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1

[57577.099793] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57577.099794]  likely on CPU 2 (core 2, socket 0)

[57577.099802] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57582.429196] coredump: 3082(cosmic-applet-n): over core_pipe_limit, skipping core dump
[57582.430327] coredump: 154513(cosmic-panel-bu): over core_pipe_limit, skipping core dump
[57582.430391] coredump: 3107(cosmic-app-list): over core_pipe_limit, skipping core dump
[57582.430445] coredump: 3106(cosmic-panel-bu): over core_pipe_limit, skipping core dump
[57582.432085] coredump: 3089(smithay-clipboa): over core_pipe_limit, skipping core dump
[57582.434425] coredump: 3091(cosmic-panel-bu): over core_pipe_limit, skipping core dump
[57582.437380] coredump: 3086(cosmic-applet-p): over core_pipe_limit, skipping core dump
[57587.557466] llvmpipe-4[170364]: segfault at 2c100 ip 000077c754065374 sp 000077c76fffe3a0 error 4 likely on CPU 0 (core 0, socket 0)
[57587.557477] llvmpipe-1[170361]: segfault at 200 ip 000077c754065374 sp 000077c7a4baa400 error 4
[57587.557480] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57587.557485]  likely on CPU 7 (core 1, socket 0)
[57587.557484] llvmpipe-3[170363]: segfault at 300 ip 000077c754065374 sp 000077c775a90400 error 4

[57587.557492] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57587.557494]  likely on CPU 8 (core 2, socket 0)
[57587.557499] Code: dd fe fb c5 d5 fe db c5 cd fe e4 c5 cd fe ed c4 c1 7d 6f 32 c4 62 75 00 c6 c4 62 6d 00 e6 c5 f5 76 c9 c5 c9 ef f6 c5 e9 ef d2 <c4> e2 75 90 34 3f c5 c1 ef ff c5 f5 76 c9 c4 e2 75 90 3c 1f c5 e1
[57587.768707] i915 0000:0c:00.0: [drm] HPD interrupt storm detected on connector HDMI-A-2: switching from hotplug detection to polling
[57590.024677] coredump: 170672(cosmic-panel-bu): over core_pipe_limit, skipping core dump
[57590.026470] coredump: 170638(smithay-clipboa): over core_pipe_limit, skipping core dump
[57590.026541] coredump: 170648(smithay-clipboa): over core_pipe_limit, skipping core dump
[57590.026650] coredump: 170562(cosmic-panel-bu): over core_pipe_limit, skipping core dump
[57590.032042] coredump: 170644(cosmic-applet-w): over core_pipe_limit, skipping core dump
[57590.033912] coredump: 170546(cosmic-panel-bu): over core_pipe_limit, skipping core dump
[57590.035778] coredump: 170573(cosmic-applet-a): over core_pipe_limit, skipping core dump
[57660.767497] usb 2-1: current rate 16000 is different from the runtime rate 48000
[57660.831975] usb 2-1: current rate 16000 is different from the runtime rate 48000
[57660.895360] usb 2-1: current rate 16000 is different from the runtime rate 48000
[57672.000477] usb 5-3: USB disconnect, device number 3