and the !CONFIG_JUMP_LABEL version of static_branch_unlikely() uses
static_key_enabled(), which uses static_key_count(), which uses
atomic_read(), which calls instrument_atomic_read(), which uses
kasan_check_read(), which is __kasan_check_read().
Let's permit these KASAN helpers in UACCESS regions - static keys should
probably work under UACCESS, I think.
PeterZ adds:
It's not a matter of permitting, it's a matter of being safe and
correct. In this case it is, because it's a thin wrapper around
check_memory_region() which was already marked safe.
check_memory_region() is correct because the only thing it ends up
calling is kasa_report() and that is also marked safe because that is
annotated with user_access_save/restore() before it does anything else.
On top of that, all of KASAN is noinstr, so nothing in here will end up
in tracing and/or call schedule() before the user_access_save().