selftests/bpf: Add tests for rbtree API interaction in sleepable progs
Confirm that the following sleepable prog states fail verification:
* bpf_rcu_read_unlock before bpf_spin_unlock
* RCU CS will last at least as long as spin_lock CS
Also confirm that correct usage passes verification, specifically:
* Explicit use of bpf_rcu_read_{lock, unlock} in sleepable test prog
* Implied RCU CS due to spin_lock CS
None of the selftest progs actually attach to bpf_testmod's
bpf_testmod_test_read.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230821193311.3290257-8-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>