selftests/bpf: Test btf lookup helper sleepability

Add an expected failure case which calls
bpf_btf_find_by_name_kind() from a BPF timer callback. Without the
helper prototype being marked sleepable, the verifier accepts the
program and the load unexpectedly succeeds.

Also add a positive control which calls the helper directly from a
syscall program. This verifies that marking the helper sleepable only
rejects it in non-sleepable regions.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260903214758.2727663-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Kumar Kartikeya Dwivedi 2026-09-03 23:47:50 +02:00 • committed by Alexei Starovoitov
commit 687b2729ce