Re: [PATCH 33/35] selftests/x86: Add map_shadow_stack syscall test

[Dave Hansen]

On 1/30/22 13:18, Rick Edgecombe wrote:
> Add a simple selftest for exercising the new map_shadow_stack syscall.

This is a good start for the selftest.  But, it would be really nice to
see a few additional smoke tests in here that are independent of the
library support.

For instance, it would be nice to have tests that:

1. Write to the shadow stack with normal instructions (and recover from
   the inevitable SEGV).  Make sure the siginfo looks like we expect.
2. Corrupt the regular stack, or maybe just use a retpoline
   do induce a shadow stack exception.  Ditto on checking the siginfo
3. Do enough CALLs that will likely trigger a fault and an on-demand
   shadow stack page allocation.

That will test the *basics* and should be pretty simple to write.