[BUG] Win10 VM crashed when VNC connected.

[AndrewYu]

I am running FreeNAS-11.3-U4.1 on
AMD Ryzen 5 3500X,
48G RAM,
ASUS C6H MB.

I have allocated 8GB of RAM and 40 GB of pool to Win10 VM and only ran one small program .
VNC worked fine When VM started a while.
Maybe few hours later, If you try to connect again, it will crash immediately.

Those are part of reports.

Code:

[2020-08-26 08:56:59,259] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59   other clients:
[2020-08-26 08:56:59,311] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Client Protocol Version 3.8
[2020-08-26 08:56:59,311] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Protocol version sent 3.8, using 3.8
[2020-08-26 08:56:59,318] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 rfbProcessClientSecurityType: executing handler for type 1
[2020-08-26 08:56:59,319] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 rfbProcessClientSecurityType: returning securityResult for client rfb version >= 3.8
[2020-08-26 08:56:59,334] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Pixel format for client 127.0.0.1:
[2020-08-26 08:56:59,334] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59   32 bpp, depth 24, little endian
[2020-08-26 08:56:59,334] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59   true colour: max r 255 g 255 b 255, shift r 16 g 8 b 0
[2020-08-26 08:56:59,436] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Using image quality level 6 for client 127.0.0.1
[2020-08-26 08:56:59,436] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Using JPEG subsampling 0, Q79 for client 127.0.0.1
[2020-08-26 08:56:59,436] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Using compression level 2 for client 127.0.0.1
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Enabling NewFBSize protocol extension for client 127.0.0.1
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Enabling LastRect protocol extension for client 127.0.0.1
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0xFFFFFEFE)
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0xFFFFFECC)
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0xFFFFFEC8)
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 rfbProcessClientNormalMessage: ignoring unsupported encoding type Enc(0xFFFFFEC7)
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Enabling full-color cursor updates for client 127.0.0.1
[2020-08-26 08:56:59,437] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:56:59 Using tight encoding for client 127.0.0.1
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06 Client 127.0.0.1 gone
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06 Statistics             events    Transmit/ RawEquiv ( saved)
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  FramebufferUpdate   :     36 |         0/        0 (  0.0%)
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  LastRect            :     36 |       432/      432 (  0.0%)
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  tight               :   1267 |   4387021/113261412 ( 96.1%)
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  RichCursor          :      1 |       255/      255 (  0.0%)
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  TOTALS              :   1340 |   4387708/113262099 ( 96.1%)
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06 Statistics             events    Received/ RawEquiv ( saved)
[2020-08-26 08:57:06,943] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  PointerEvent        :    149 |       894/      894 (  0.0%)
[2020-08-26 08:57:06,944] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  FramebufferUpdate   :     37 |       370/      370 (  0.0%)
[2020-08-26 08:57:06,944] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  SetEncodings        :      1 |        68/       68 (  0.0%)
[2020-08-26 08:57:06,944] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  SetPixelFormat      :      1 |        20/       20 (  0.0%)
[2020-08-26 08:57:06,944] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 08:57:06  TOTALS              :    188 |      1352/     1352 (  0.0%)
[2020-08-26 15:05:28,451] (DEBUG) VMService.vm_3.run():315 - VM_Win10: 26/08/2020 15:05:28   other clients:
[2020-08-26 15:05:29,557] (INFO) VMService.vm_3.run():346 - ===> Error VM: VM_Win10 ID: 3 BHYVE_CODE: -11
[2020-08-26 15:05:29,568] (ERROR) VMService.vm_3.running():490 - ===> VMM VM_Win10 is running without bhyve process.
[2020-08-26 15:05:29,571] (DEBUG) VMService.vm_3.__teardown_guest_vmemory():376 - ===> Give back guest memory to ARC: 49042055168
[2020-08-26 15:05:29,571] (WARNING) VMService.vm_3.destroy_vm():353 - ===> Destroying VM: VM_Win10 ID: 3 BHYVE_CODE: -11