All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH bpf-next v4 1/2] bpf: Search and add kfuncs in struct_ops prologue and epilogue
@ 2025-02-25 21:29 Amery Hung
  2025-02-25 21:29 ` [PATCH bpf-next v4 2/2] selftests/bpf: Test gen_pro/epilogue that generate kfuncs Amery Hung
  2025-02-25 21:54 ` [PATCH bpf-next v4 1/2] bpf: Search and add kfuncs in struct_ops prologue and epilogue Martin KaFai Lau
  0 siblings, 2 replies; 5+ messages in thread
From: Amery Hung @ 2025-02-25 21:29 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] 5+ messages in thread
end of thread, other threads:[~2025-02-25 22:02 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-02-25 21:29 [PATCH bpf-next v4 1/2] bpf: Search and add kfuncs in struct_ops prologue and epilogue Amery Hung
2025-02-25 21:29 ` [PATCH bpf-next v4 2/2] selftests/bpf: Test gen_pro/epilogue that generate kfuncs Amery Hung
2025-02-25 21:58   ` Martin KaFai Lau
2025-02-25 22:02     ` Amery Hung
2025-02-25 21:54 ` [PATCH bpf-next v4 1/2] bpf: Search and add kfuncs in struct_ops prologue and epilogue Martin KaFai Lau

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.