selftests/bpf: fix segfault of test_progs when prog loading failed
The test_progs subtests, test_spin_lock() and test_map_lock(),
requires BTF present to run successfully.
Currently, when BTF failed to load, test_progs will segfault,
$ ./test_progs
...
12: (bf) r1 = r8
13: (85) call bpf_spin_lock#93
map 'hash_map' has to have BTF in order to use bpf_spin_lock
libbpf: -- END LOG --
libbpf: failed to load program 'map_lock_demo'
libbpf: failed to load object './test_map_lock.o'
test_map_lock:bpf_prog_load errno 13
Segmentation fault
The segfault is caused by uninitialized variable "obj", which
is used in bpf_object__close(obj), when bpf prog failed to load.
Initializing variable "obj" to NULL in two occasions fixed the problem.
$ ./test_progs
...
Summary: 219 PASSED, 2 FAILED
Fixes: 7b0ba7a02bd0 ("selftests/bpf: add bpf_spin_lock verifier tests") Fixes: 544b028ffe74 ("selftests/bpf: test for BPF_F_LOCK") Reported-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>