diff options
| author | Andrii Nakryiko | 2023-12-02 09:57:03 -0800 |
|---|---|---|
| committer | Alexei Starovoitov | 2023-12-02 11:36:51 -0800 |
| commit | e02dea158ddaebe6e725be715e0009923b96ec8e (patch) | |
| tree | 188fa71703b207c98697a36cc1f76984493a22d2 /tools | |
| parent | eabe518de533a4291996020977054a7a7b78c7d3 (diff) | |
selftests/bpf: validate async callback return value check correctness
Adjust timer/timer_ret_1 test to validate more carefully verifier logic
of enforcing async callback return value. This test will pass only if
return result is marked precise and read.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231202175705.885270-10-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/timer_failure.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/tools/testing/selftests/bpf/progs/timer_failure.c b/tools/testing/selftests/bpf/progs/timer_failure.c index 9000da1e2120..9fbc69c77bbb 100644 --- a/tools/testing/selftests/bpf/progs/timer_failure.c +++ b/tools/testing/selftests/bpf/progs/timer_failure.c @@ -21,17 +21,37 @@ struct { __type(value, struct elem); } timer_map SEC(".maps"); -static int timer_cb_ret1(void *map, int *key, struct bpf_timer *timer) +__naked __noinline __used +static unsigned long timer_cb_ret_bad() { - if (bpf_get_smp_processor_id() % 2) - return 1; - else - return 0; + asm volatile ( + "call %[bpf_get_prandom_u32];" + "if r0 s> 1000 goto 1f;" + "r0 = 0;" + "1:" + "goto +0;" /* checkpoint */ + /* async callback is expected to return 0, so branch above + * skipping r0 = 0; should lead to a failure, but if exit + * instruction doesn't enforce r0's precision, this callback + * will be successfully verified + */ + "exit;" + : + : __imm(bpf_get_prandom_u32) + : __clobber_common + ); } SEC("fentry/bpf_fentry_test1") -__failure __msg("should have been in [0, 0]") -int BPF_PROG2(test_ret_1, int, a) +__log_level(2) +__flag(BPF_F_TEST_STATE_FREQ) +__failure +/* check that fallthrough code path marks r0 as precise */ +__msg("mark_precise: frame0: regs=r0 stack= before 22: (b7) r0 = 0") +/* check that branch code path marks r0 as precise */ +__msg("mark_precise: frame0: regs=r0 stack= before 24: (85) call bpf_get_prandom_u32#7") +__msg("should have been in [0, 0]") +long BPF_PROG2(test_bad_ret, int, a) { int key = 0; struct bpf_timer *timer; @@ -39,7 +59,7 @@ int BPF_PROG2(test_ret_1, int, a) timer = bpf_map_lookup_elem(&timer_map, &key); if (timer) { bpf_timer_init(timer, &timer_map, CLOCK_BOOTTIME); - bpf_timer_set_callback(timer, timer_cb_ret1); + bpf_timer_set_callback(timer, timer_cb_ret_bad); bpf_timer_start(timer, 1000, 0); } |