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From: Eduard Zingerman <eddyz87@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org
Cc: andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev,
	kernel-team@fb.com, yonghong.song@linux.dev,
	Eduard Zingerman <eddyz87@gmail.com>
Subject: [PATCH bpf-next v1 03/11] bpf: frame_insn_idx() utility function
Date: Sat, 24 May 2025 12:19:24 -0700	[thread overview]
Message-ID: <20250524191932.389444-4-eddyz87@gmail.com> (raw)
In-Reply-To: <20250524191932.389444-1-eddyz87@gmail.com>

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: Eduard Zingerman <eddyz87@gmail.com>
---
 kernel/bpf/verifier.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 23c7136ab6ae..13bbe63dab00 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1963,6 +1963,14 @@ 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;
@@ -18765,9 +18773,7 @@ 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))
@@ -19460,6 +19466,7 @@ 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);
-- 
2.48.1


  parent reply	other threads:[~2025-05-24 19:19 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-24 19:19 [PATCH bpf-next v1 00/11] bpf: propagate read/precision marks over state graph backedges Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 01/11] Revert "bpf: use common instruction history across all states" Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 02/11] bpf: compute SCCs in program control flow graph Eduard Zingerman
2025-05-24 19:19 ` Eduard Zingerman [this message]
2025-05-24 19:19 ` [PATCH bpf-next v1 04/11] bpf: starting_state parameter for __mark_chain_precision() Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 05/11] bpf: set 'changed' status if propagate_precision() did any updates Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 06/11] bpf: set 'changed' status if propagate_liveness() " Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 07/11] bpf: move REG_LIVE_DONE check to clean_live_states() Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 08/11] bpf: propagate read/precision marks over state graph backedges Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 09/11] bpf: remove {update,get}_loop_entry functions Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 10/11] bpf: include backedges in peak_states stat Eduard Zingerman
2025-05-24 19:19 ` [PATCH bpf-next v1 11/11] selftests/bpf: tests with a loop state missing read/precision mark Eduard Zingerman
2025-05-27 21:26 ` [PATCH bpf-next v1 00/11] bpf: propagate read/precision marks over state graph backedges Eduard Zingerman
2025-06-05 23:02 ` Eduard Zingerman
2025-06-06  2:38   ` Alexei Starovoitov

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