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bpf: print liveness info to verifier log 

let verifier print register and stack liveness information
into verifier log

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Alexei Starovoitov 2017-11-30 21:31:36 -08:00 committed by Daniel Borkmann
parent 12a3cc8424
commit 4e92024a48
1 changed files with 20 additions and 4 deletions
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24
kernel/bpf/verifier.c
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@ -216,6 +216,17 @@ static const char * const reg_type_str[] = {
[PTR_TO_PACKET_END] = "pkt_end",
};
static void print_liveness(struct bpf_verifier_env *env,
enum bpf_reg_liveness live)
{
if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN))
verbose(env, "_");
if (live & REG_LIVE_READ)
verbose(env, "r");
if (live & REG_LIVE_WRITTEN)
verbose(env, "w");
}
static void print_verifier_state(struct bpf_verifier_env *env,
struct bpf_verifier_state *state)
{
@ -228,7 +239,9 @@ static void print_verifier_state(struct bpf_verifier_env *env,
t = reg->type;
if (t == NOT_INIT)
continue;
verbose(env, " R%d=%s", i, reg_type_str[t]);
verbose(env, " R%d", i);
print_liveness(env, reg->live);
verbose(env, "=%s", reg_type_str[t]);
if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
tnum_is_const(reg->var_off)) {
/* reg->off should be 0 for SCALAR_VALUE */
@ -277,10 +290,13 @@ 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=%s",
(-i - 1) * BPF_REG_SIZE,
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);
verbose(env, "=%s",
reg_type_str[state->stack[i].spilled_ptr.type]);
}
}
verbose(env, "\n");
}