[PATCH bpf-next v2 7/7] bpf: print full verifier states on infinite loop detection

[Eduard Zingerman <eddyz87@gmail.com>]

Additional logging in is_state_visited(): if infinite loop is detected
print full verifier state for both current and equivalent states.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 kernel/bpf/verifier.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index baf31b61b3ff..a91aa8638dba 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -16927,6 +16927,10 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 			    !iter_active_depths_differ(&sl->state, cur)) {
 				verbose_linfo(env, insn_idx, "; ");
 				verbose(env, "infinite loop detected at insn %d\n", insn_idx);
+				verbose(env, "cur state:");
+				print_verifier_state(env, cur->frame[cur->curframe], true);
+				verbose(env, "old state:");
+				print_verifier_state(env, sl->state.frame[cur->curframe], true);
 				return -EINVAL;
 			}
 			/* if the verifier is processing a loop, avoid adding new state
-- 
2.42.0