- kern_kcov.c needs to be compiled with -fsanitize=kernel-memory when
KMSAN is configured since it calls into various other subsystems.
- Disable address and memory sanitizers in kcov(4)'s coverage sanitizer
callbacks, as they do not provide useful checking. Moreover, with
KMSAN we may otherwise get false positives since the caller (coverage
sanitizer runtime) is not instrumented.
- Disable KASAN and KMSAN interceptors in subr_coverage.c, as they do
not provide any benefit but do introduce overhead when fuzzing.
Sponsored by: The FreeBSD Foundation
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