Otherwise the local mallocs variable is not decremented correctly (if
TEST_SUITES is defined) and the fuzzing setup (i.e. when MODULE_FUZZING
is defined) does not terminate. This regression was introduced in
3970b667aa.
Since RIOT is an operating system the native binary will never terminate
[0]. The termination condition for fuzzing GNRC is that the packet was
handled by the network stack and therefore freed. If it is never freed
we will deadlock meaning a memory leak was found, afl should be able to
detect this through timeouts.
This is currently only supported for gnrc_pktbuf_malloc since this is
the pktbuf implementation I used for fuzzing. Implementing this in
pktbuf.h is not possible.
[0]: Except NATIVE_AUTO_EXIT is defined, however, even with that define
set RIOT will only terminate when all threads terminated. Unfortunately,
gnrc_udp and other network threads will never terminate.
Size 0 snips are legal packet snips (empty payload e.g.) so it doesn't
make sense to issue an error in the write-protection in that case.
API documentation doesn't mention it either and the tests still pass
with the check removed.
