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bpf: honor env->test_state_freq flag in is_state_visited()

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env->test_state_freq flag can be set by user by passing
BPF_F_TEST_STATE_FREQ program flag. This is used in a bunch of selftests
to have predictable state checkpoints at every jump and so on.

Currently, bounded loop handling heuristic ignores this flag if number
of processed jumps and/or number of processed instructions is below some
thresholds, which throws off that reliable state checkpointing.

Honor this flag in all circumstances by disabling heuristic if
env->test_state_freq is set.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko 2023-03-02 15:50:02 -08:00 committed by Alexei Starovoitov
parent 6f876e75d3
commit 98ddcf389d
1 changed files with 2 additions and 1 deletions
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3
kernel/bpf/verifier.c
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@ -14651,7 +14651,8 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
* This threshold shouldn't be too high either, since states
* at the end of the loop are likely to be useful in pruning.
*/
if (env->jmps_processed - env->prev_jmps_processed < 20 &&
if (!env->test_state_freq &&
env->jmps_processed - env->prev_jmps_processed < 20 &&
env->insn_processed - env->prev_insn_processed < 100)
add_new_state = false;
goto miss;