Commit 13f843c0 authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Alexei Starovoitov
Browse files

bpf: frame_insn_idx() utility function 



A function to return IP for a given frame in a call stack of a state.
Will be used by a next patch.

The `state->insn_idx = env->insn_idx;` assignment in the do_check()
allows to use frame_insn_idx with env->cur_state.
At the moment bpf_verifier_state->insn_idx is set when new cached
state is added in is_state_visited() and accessed only in the contexts
when the state is already in the cache. Hence this assignment does not
change verifier behaviour.

Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250611200836.4135542-3-eddyz87@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 96c6aa4c

kernel/bpf/verifier.c

+10 −3
Original line number Diff line number Diff line
@@ -1964,6 +1964,14 @@ static void update_loop_entry(struct bpf_verifier_env *env, 
	}

}









/* Return IP for a given frame in a call stack */









static u32 frame_insn_idx(struct bpf_verifier_state *st, u32 frame)









{









	return frame == st->curframe









	       ? st->insn_idx









	       : st->frame[frame + 1]->callsite;









}

















static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)









{









	struct bpf_verifier_state_list *sl = NULL, *parent_sl;








@@ -18790,9 +18798,7 @@ static bool states_equal(struct bpf_verifier_env *env,







	 * and all frame states need to be equivalent









	 */









	for (i = 0; i <= old->curframe; i++) {









		insn_idx = i == old->curframe









			   ? env->insn_idx









			   : old->frame[i + 1]->callsite;









		insn_idx = frame_insn_idx(old, i);









		if (old->frame[i]->callsite != cur->frame[i]->callsite)









			return false;









		if (!func_states_equal(env, old->frame[i], cur->frame[i], insn_idx, exact))








@@ -19687,6 +19693,7 @@ static int do_check(struct bpf_verifier_env *env)







		}

















		state->last_insn_idx = env->prev_insn_idx;









		state->insn_idx = env->insn_idx;

















		if (is_prune_point(env, env->insn_idx)) {









			err = is_state_visited(env, env->insn_idx);