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selftests/bpf: fix segfault of test_progs when prog loading failed

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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: b4d4556c32 ("selftests/bpf: add bpf_spin_lock verifier tests")
Fixes: ba72a7b4ba ("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>
This commit is contained in:
Yonghong Song 2019-03-11 22:21:09 -07:00 committed by Daniel Borkmann
parent f38a1f0a5a
commit d6f1837107
2 changed files with 2 additions and 2 deletions
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2
tools/testing/selftests/bpf/prog_tests/map_lock.c
View File

@ -37,7 +37,7 @@ void test_map_lock(void)
const char *file = "./test_map_lock.o";
int prog_fd, map_fd[2], vars[17] = {};
pthread_t thread_id[6];
struct bpf_object *obj;
struct bpf_object *obj = NULL;
int err = 0, key = 0, i;
void *ret;

2
tools/testing/selftests/bpf/prog_tests/spinlock.c
View File

@ -5,7 +5,7 @@ void test_spinlock(void)
{
const char *file = "./test_spin_lock.o";
pthread_t thread_id[4];
struct bpf_object *obj;
struct bpf_object *obj = NULL;
int prog_fd;
int err = 0, i;
void *ret;