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Groups > linux.kernel > #1703230

[PATCH v4 net-next 04/13] bpf/verifier: more concise register state logs for constant var_off

From Edward Cree <ecree@solarflare.com>
Newsgroups linux.kernel
Subject [PATCH v4 net-next 04/13] bpf/verifier: more concise register state logs for constant var_off
Date 2017-08-03 18:20 +0200
Message-ID <uar0R-2qL-3@gated-at.bofh.it> (permalink)
References <uaqRc-2ml-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


Signed-off-by: Edward Cree <ecree@solarflare.com>
---
 kernel/bpf/verifier.c | 46 +++++++++++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 19 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ca14f59..2924b01 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -234,25 +234,33 @@ static void print_verifier_state(struct bpf_verifier_state *state)
 				verbose(",ks=%d,vs=%d",
 					reg->map_ptr->key_size,
 					reg->map_ptr->value_size);
-			if (reg->smin_value != reg->umin_value &&
-			    reg->smin_value != S64_MIN)
-				verbose(",smin_value=%lld",
-					(long long)reg->smin_value);
-			if (reg->smax_value != reg->umax_value &&
-			    reg->smax_value != S64_MAX)
-				verbose(",smax_value=%lld",
-					(long long)reg->smax_value);
-			if (reg->umin_value != 0)
-				verbose(",umin_value=%llu",
-					(unsigned long long)reg->umin_value);
-			if (reg->umax_value != U64_MAX)
-				verbose(",umax_value=%llu",
-					(unsigned long long)reg->umax_value);
-			if (!tnum_is_unknown(reg->var_off)) {
-				char tn_buf[48];
-
-				tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
-				verbose(",var_off=%s", tn_buf);
+			if (tnum_is_const(reg->var_off)) {
+				/* Typically an immediate SCALAR_VALUE, but
+				 * could be a pointer whose offset is too big
+				 * for reg->off
+				 */
+				verbose(",imm=%llx", reg->var_off.value);
+			} else {
+				if (reg->smin_value != reg->umin_value &&
+				    reg->smin_value != S64_MIN)
+					verbose(",smin_value=%lld",
+						(long long)reg->smin_value);
+				if (reg->smax_value != reg->umax_value &&
+				    reg->smax_value != S64_MAX)
+					verbose(",smax_value=%lld",
+						(long long)reg->smax_value);
+				if (reg->umin_value != 0)
+					verbose(",umin_value=%llu",
+						(unsigned long long)reg->umin_value);
+				if (reg->umax_value != U64_MAX)
+					verbose(",umax_value=%llu",
+						(unsigned long long)reg->umax_value);
+				if (!tnum_is_unknown(reg->var_off)) {
+					char tn_buf[48];
+
+					tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+					verbose(",var_off=%s", tn_buf);
+				}
 			}
 			verbose(")");
 		}

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Thread

[PATCH v4 net-next 00/13] bpf: rewrite value tracking in verifier Edward Cree <ecree@solarflare.com> - 2017-08-03 18:10 +0200
  [PATCH v4 net-next 04/13] bpf/verifier: more concise register state  logs for constant var_off Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 11/13] selftests/bpf: variable offset negative  tests Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 08/13] selftests/bpf: add test for bogus  operations on pointers Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 07/13] selftests/bpf: add a test to test_align Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 09/13] selftests/bpf: don't try to access past  MAX_PACKET_OFF in test_verifier Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 05/13] selftests/bpf: change test_verifier  expectations Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 02/13] nfp: change bpf verifier hooks to match new  verifier data structures Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
    Re: [PATCH v4 net-next 02/13] nfp: change bpf verifier hooks to  match new verifier data structures David Miller <davem@davemloft.net> - 2017-08-07 06:10 +0200
  [PATCH v4 net-next 13/13] bpf/verifier: increase complexity limit to  128k Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 06/13] selftests/bpf: rewrite test_align Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 10/13] selftests/bpf: add tests for subtraction &  negative numbers Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  [PATCH v4 net-next 12/13] Documentation: describe the new eBPF  verifier value tracking behaviour Edward Cree <ecree@solarflare.com> - 2017-08-03 18:20 +0200
  Re: [PATCH v4 net-next 01/13] bpf/verifier: rework value tracking Daniel Borkmann <daniel@iogearbox.net> - 2017-08-07 01:40 +0200
    Re: [PATCH v4 net-next 01/13] bpf/verifier: rework value tracking Edward Cree <ecree@solarflare.com> - 2017-08-07 14:40 +0200

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