UserAgent: Mozilla/5.0 (X11; CrOS x86_64 10718.4.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.4 Safari/537.36
Platform: 10718.4.0 (Official Build) dev-channel eve

Steps to reproduce the problem:
Install numpy inside the Termina environment and attempt to invert a matrix:

$ sudo apt install python-numpy
$ python -c 'import numpy as np; np.linalg.inv(np.identity(3))'

What is the expected behavior?
`numpy` functions properly and the `python -c` returns quickly.

What went wrong?
`np.linalg.inv` hangs forever.

Did this work before? N/A 

Chrome version: 68.0.3440.4  Channel: dev
OS Version: 10718.4.0
Flash Version: 

I traced the hang, and the short story is that openblas looks up the L2 cache size on startup to pick a stride for matrix operations using CPUID:

https://github.com/xianyi/OpenBLAS/blob/1a49fb1c05b19f5bcfed1922cba9b28fed6d68c2/kernel/setparam-ref.c#L654-L671

CrosVM returns all-0s for that CPUID leaf:

[nelhage@penguin:~]$ cpuid -r -l 0x80000006
CPU 0:
   0x80000006 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
CPU 1:
   0x80000006 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
CPU 2:
   0x80000006 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
CPU 3:
   0x80000006 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000

and openblas does not check for errors and happily tries to loop over input with a stride length of 0, resulting in infinite loops in most operations.