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From: Alexei Starovoitov <ast@fb.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
	John Fastabend <john.fastabend@gmail.com>,
	<netdev@vger.kernel.org>, <kernel-team@fb.com>
Subject: [PATCH net-next 2/7] bpf: print liveness info to verifier log
Date: Thu, 30 Nov 2017 21:31:36 -0800	[thread overview]
Message-ID: <20171201053141.3992592-3-ast@fb.com> (raw)
In-Reply-To: <20171201053141.3992592-1-ast@fb.com>

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>
---
 kernel/bpf/verifier.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 71a9429fdbb5..f7229390c279 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -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");
 }
-- 
2.9.5

  parent reply	other threads:[~2017-12-01  5:31 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-01  5:31 [PATCH net-next 0/7] bpf: verifier improvements and cleanups Alexei Starovoitov
2017-12-01  5:31 ` [PATCH net-next 1/7] bpf: fix stack state printing in verifier log Alexei Starovoitov
2017-12-01  5:31 ` Alexei Starovoitov [this message]
2017-12-01  5:31 ` [PATCH net-next 3/7] bpf: don't mark FP reg as uninit Alexei Starovoitov
2017-12-01  5:31 ` [PATCH net-next 4/7] bpf: improve verifier liveness marks Alexei Starovoitov
2017-12-01  5:31 ` [PATCH net-next 5/7] bpf: improve JEQ/JNE path walking Alexei Starovoitov
2017-12-01  5:31 ` [PATCH net-next 6/7] bpf: cleanup register_is_null() Alexei Starovoitov
2017-12-01  5:31 ` [PATCH net-next 7/7] selftests/bpf: adjust test_align expected output Alexei Starovoitov
2017-12-01 10:28 ` [PATCH net-next 0/7] bpf: verifier improvements and cleanups Daniel Borkmann

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