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* [PATCH bpf-next v3 1/2] bpf: Search and add kfuncs in struct_ops prologue and epilogue
@ 2025-02-21 16:47 Amery Hung
  2025-02-21 16:47 ` [PATCH bpf-next v3 2/2] selftests/bpf: Test gen_pro/epilogue that generate kfuncs Amery Hung
  0 siblings, 1 reply; 4+ messages in thread
From: Amery Hung @ 2025-02-21 16:47 UTC (permalink / raw)
  To: bpf
  Cc: daniel, andrii, alexei.starovoitov, martin.lau, eddyz87,
	ameryhung, kernel-team

From: Amery Hung <amery.hung@bytedance.com>

Currently, add_kfunc_call() is only invoked once before the main
verification loop. Therefore, the verifier could not find the
bpf_kfunc_btf_tab of a new kfunc call which is not seen in user defined
struct_ops operators but introduced in gen_prologue or gen_epilogue
during do_misc_fixup(). Fix this by searching kfuncs in the patching
instruction buffer and add them to prog->aux->kfunc_tab.

Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
---
 kernel/bpf/verifier.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8f1df279e432..212b487fd39d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3215,6 +3215,21 @@ bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
 	return res ? &res->func_model : NULL;
 }
 
+static int add_kfunc_in_insns(struct bpf_verifier_env *env,
+			      struct bpf_insn *insn, int cnt)
+{
+	int i, ret;
+
+	for (i = 0; i < cnt; i++, insn++) {
+		if (bpf_pseudo_kfunc_call(insn)) {
+			ret = add_kfunc_call(env, insn->imm, insn->off);
+			if (ret < 0)
+				return ret;
+		}
+	}
+	return 0;
+}
+
 static int add_subprog_and_kfunc(struct bpf_verifier_env *env)
 {
 	struct bpf_subprog_info *subprog = env->subprog_info;
@@ -20368,7 +20383,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 {
 	struct bpf_subprog_info *subprogs = env->subprog_info;
 	const struct bpf_verifier_ops *ops = env->ops;
-	int i, cnt, size, ctx_field_size, delta = 0, epilogue_cnt = 0;
+	int i, cnt, size, ctx_field_size, ret, delta = 0, epilogue_cnt = 0;
 	const int insn_cnt = env->prog->len;
 	struct bpf_insn *epilogue_buf = env->epilogue_buf;
 	struct bpf_insn *insn_buf = env->insn_buf;
@@ -20397,6 +20412,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 				return -ENOMEM;
 			env->prog = new_prog;
 			delta += cnt - 1;
+
+			ret = add_kfunc_in_insns(env, epilogue_buf, epilogue_cnt - 1);
+			if (ret < 0)
+				return ret;
 		}
 	}
 
@@ -20417,6 +20436,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 
 			env->prog = new_prog;
 			delta += cnt - 1;
+
+			ret = add_kfunc_in_insns(env, insn_buf, cnt - 1);
+			if (ret < 0)
+				return ret;
 		}
 	}
 
-- 
2.47.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-02-25 21:12 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-02-21 16:47 [PATCH bpf-next v3 1/2] bpf: Search and add kfuncs in struct_ops prologue and epilogue Amery Hung
2025-02-21 16:47 ` [PATCH bpf-next v3 2/2] selftests/bpf: Test gen_pro/epilogue that generate kfuncs Amery Hung
2025-02-25 20:53   ` Martin KaFai Lau
2025-02-25 21:12     ` Amery Hung

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