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| author | Andrii Nakryiko <andrii@kernel.org> | 2023-05-04 21:33:11 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-05-04 22:35:35 -0700 |
| commit | d9439c21a9e4769bfd83a03ab39056164d44ac31 (patch) | |
| tree | d77acf3952f22e5f5a1805e923038ce3d17f70a9 /include/linux/bpf_verifier.h | |
| parent | 407958a0e980b9e1842ab87b5a1040521e1e24e9 (diff) | |
| download | lwn-d9439c21a9e4769bfd83a03ab39056164d44ac31.tar.gz lwn-d9439c21a9e4769bfd83a03ab39056164d44ac31.zip | |
bpf: improve precision backtrack logging
Add helper to format register and stack masks in more human-readable
format. Adjust logging a bit during backtrack propagation and especially
during forcing precision fallback logic to make it clearer what's going
on (with log_level=2, of course), and also start reporting affected
frame depth. This is in preparation for having more than one active
frame later when precision propagation between subprog calls is added.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/linux/bpf_verifier.h')
| -rw-r--r-- | include/linux/bpf_verifier.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 33f541366f4e..5b11a3b0fec0 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -18,8 +18,11 @@ * that converting umax_value to int cannot overflow. */ #define BPF_MAX_VAR_SIZ (1 << 29) -/* size of type_str_buf in bpf_verifier. */ -#define TYPE_STR_BUF_LEN 128 +/* size of tmp_str_buf in bpf_verifier. + * we need at least 306 bytes to fit full stack mask representation + * (in the "-8,-16,...,-512" form) + */ +#define TMP_STR_BUF_LEN 320 /* Liveness marks, used for registers and spilled-regs (in stack slots). * Read marks propagate upwards until they find a write mark; they record that @@ -620,8 +623,10 @@ struct bpf_verifier_env { /* Same as scratched_regs but for stack slots */ u64 scratched_stack_slots; u64 prev_log_pos, prev_insn_print_pos; - /* buffer used in reg_type_str() to generate reg_type string */ - char type_str_buf[TYPE_STR_BUF_LEN]; + /* buffer used to generate temporary string representations, + * e.g., in reg_type_str() to generate reg_type string + */ + char tmp_str_buf[TMP_STR_BUF_LEN]; }; __printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log, |