On Wed, 23 Oct 2019 17:24:28 +0200 Andrey Konovalov [off-list ref] wrote:

This patchset extends kcov to allow collecting coverage from the USB
subsystem and vhost workers. See the first patch description for details
about the kcov extension. The other two patches apply this kcov extension
to USB and vhost.

These patches have been used to enable coverage-guided USB fuzzing with
syzkaller for the last few years

I find it surprising that this material is so focused on USB.  Is
there something unique about USB that gave rise to this situation, or
is it expected that the new kcov feature will be used elsewhere in the
kernel?

If the latter, which are the expected subsystems?