linux.git/tools/testing/selftests/bpf/prog_tests/btf_map_keyless.c, branch master Linux kernel source tree selftests/bpf: Add test for key-less BTF hash map 2026-09-03T16:31:52+00:00 Jiayuan Chen jiayuan.chen@linux.dev 2026-09-01T10:47:38+00:00 6265b44f2c3bb2839a306d6088d6e65a58d7e80e Create a hash and an rhash map with btf_key_type_id == 0 and expect bpf_map_create() to fail with -EINVAL; a positive control with a real key type confirms the rejection is about the key-less BTF and not some unrelated failure. Such a map used to be accepted and then NULL-deref in btf_type_show() when dumped through bpffs. Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Link: https://lore.kernel.org/r/20260901104924.346187-5-jiayuan.chen@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
Create a hash and an rhash map with btf_key_type_id == 0 and expect
bpf_map_create() to fail with -EINVAL; a positive control with a real
key type confirms the rejection is about the key-less BTF and not some
unrelated failure.

Such a map used to be accepted and then NULL-deref in btf_type_show()
when dumped through bpffs.

Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20260901104924.346187-5-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>