Commit 4e92024a authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

bpf: print liveness info to verifier log 



let verifier print register and stack liveness information
into verifier log

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 12a3cc84

kernel/bpf/verifier.c

+20 −4
Original line number Diff line number Diff line
@@ -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 */
@@ -277,11 +290,14 @@ 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");

}