diff options
| author | Edward Cree <ecree@solarflare.com> | 2018-08-22 21:02:44 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2018-08-30 03:52:12 +0200 |
| commit | 8efea21d333d21e1f9177579ffdc69556314f603 (patch) | |
| tree | 6af86387e67804ce0b375367811af02fb9b04ac3 /kernel | |
| parent | bpf/verifier: per-register parent pointers (diff) | |
| download | linux-8efea21d333d21e1f9177579ffdc69556314f603.tar.xz linux-8efea21d333d21e1f9177579ffdc69556314f603.zip | |
bpf/verifier: display non-spill stack slot types in print_verifier_state
If a stack slot does not hold a spilled register (STACK_SPILL), then each
of its eight bytes could potentially have a different slot_type. This
information can be important for debugging, and previously we either did
not print anything for the stack slot, or just printed fp-X=0 in the case
where its first byte was STACK_ZERO.
Instead, print eight characters with either 0 (STACK_ZERO), m (STACK_MISC)
or ? (STACK_INVALID) for any stack slot which is neither STACK_SPILL nor
entirely STACK_INVALID.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 68568d22d6bd..f4ff0c569e54 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -263,6 +263,13 @@ static const char * const reg_type_str[] = { [PTR_TO_PACKET_END] = "pkt_end", }; +static char slot_type_char[] = { + [STACK_INVALID] = '?', + [STACK_SPILL] = 'r', + [STACK_MISC] = 'm', + [STACK_ZERO] = '0', +}; + static void print_liveness(struct bpf_verifier_env *env, enum bpf_reg_liveness live) { @@ -349,15 +356,26 @@ static void print_verifier_state(struct bpf_verifier_env *env, } } for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { - if (state->stack[i].slot_type[0] == STACK_SPILL) { - verbose(env, " fp%d", - (-i - 1) * BPF_REG_SIZE); - print_liveness(env, state->stack[i].spilled_ptr.live); + char types_buf[BPF_REG_SIZE + 1]; + bool valid = false; + int j; + + for (j = 0; j < BPF_REG_SIZE; j++) { + if (state->stack[i].slot_type[j] != STACK_INVALID) + valid = true; + types_buf[j] = slot_type_char[ + state->stack[i].slot_type[j]]; + } + types_buf[BPF_REG_SIZE] = 0; + if (!valid) + continue; + verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE); + print_liveness(env, state->stack[i].spilled_ptr.live); + if (state->stack[i].slot_type[0] == STACK_SPILL) verbose(env, "=%s", reg_type_str[state->stack[i].spilled_ptr.type]); - } - if (state->stack[i].slot_type[0] == STACK_ZERO) - verbose(env, " fp%d=0", (-i - 1) * BPF_REG_SIZE); + else + verbose(env, "=%s", types_buf); } verbose(env, "\n"); } |