61 /* For state @st look for a topmost frame with frame_insn_idx() in some SCC,
63  * call sites leading to this frame and SCC id.
66  *    void foo()  { A: loop {... SCC#1 ...}; }
67  *    void bar()  { B: loop { C: foo(); ... SCC#2 ... }
68  *                  D: loop { E: foo(); ... SCC#3 ... } }
71  * @callchain at (A) would be either (F,SCC#2) or (F,SCC#3) depending
78 	u32 i, scc, insn_idx;  in compute_scc_callchain()  local
83 		scc = env->insn_aux_data[insn_idx].scc;  in compute_scc_callchain()
84 		if (scc) {  in compute_scc_callchain()
85 			callchain->scc = scc;  in compute_scc_callchain()
100 	struct bpf_scc_info *info = env->scc_info[callchain->scc];  in scc_visit_lookup()
121 	u32 scc, num_visits;  in scc_visit_alloc()  local
124 	scc = callchain->scc;  in scc_visit_alloc()
125 	info = env->scc_info[scc];  in scc_visit_alloc()
128 	info = kvrealloc(env->scc_info[scc], new_sz, GFP_KERNEL_ACCOUNT);  in scc_visit_alloc()
131 	env->scc_info[scc] = info;  in scc_visit_alloc()
139 /* Form a string '(callsite#1,callsite#2,...,scc)' in env->tmp_str_buf */
152 	delta += snprintf(buf + delta, TMP_STR_BUF_LEN - delta, "%u)", callchain->scc);  in format_callchain()
156 /* If callchain for @st exists (@st is in some SCC), ensure that
174 			verbose(env, "SCC enter %s\n", format_callchain(env, callchain));  in maybe_enter_scc()
181 /* If callchain for @st exists (@st is in some SCC), make it empty:
195 		 * If path traversal stops inside an SCC, corresponding bpf_scc_visit  in maybe_exit_scc()
200 		 *    of any SCC.  in maybe_exit_scc()
207 			verifier_bug(env, "scc exit: no visit info for call chain %s",  in maybe_exit_scc()
216 		verbose(env, "SCC exit %s\n", format_callchain(env, callchain));  in maybe_exit_scc()
235 		verifier_bug(env, "add backedge: no SCC in verification path, insn_idx %d",  in add_scc_backedge()
246 		verbose(env, "SCC backedge %s\n", format_callchain(env, callchain));  in add_scc_backedge()
256  * if state @st is in some SCC and not all execution paths starting at this
257  * SCC are fully explored.
1437 			 *   whether the current verifier state is entering an SCC. If so, an  in bpf_is_state_visited()
1439 			 *   entering the SCC is recorded as the entry state.  in bpf_is_state_visited()
1441 			 * - This instance is associated not with the SCC itself, but with a  in bpf_is_state_visited()
1443 			 *   the SCC and the SCC id. See `compute_scc_callchain()`.  in bpf_is_state_visited()
1455 			 *   this SCC visit have been explored. `propagate_backedges()` is then  in bpf_is_state_visited()
1466 			 *     void foo() { loop { ... SCC#1 ... } }  in bpf_is_state_visited()
1473 			 * Here, there are two distinct callchains leading to SCC#1:  in bpf_is_state_visited()
1474 			 * - (A, SCC#1)  in bpf_is_state_visited()
1475 			 * - (C, SCC#1)  in bpf_is_state_visited()
1486 			 *   SCC#1, but SCC#1 would only be exited once the exploration of  in bpf_is_state_visited()