bpf: print full verifier states on infinite loop detection

Additional logging in is_state_visited(): if infinite loop is detected print full verifier state for both current and equivalent states. Acked-by: Andrii Nakryiko <[email protected]> Signed-off-by: Eduard Zingerman <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
akiyks · Oct 24, 2023 · b4d8239 · b4d8239
1 parent 64870fe
commit b4d8239
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
@@ -16928,6 +16928,10 @@ 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