linux-kernel - [PATCH bpf-next 6/6] bpf: Remove some denied functions from the btf id deny list

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Message-Id: <20230417154737.12740-7-laoar.shao@gmail.com>
Date:   Mon, 17 Apr 2023 15:47:37 +0000
From:   Yafang Shao <laoar.shao@...il.com>
To:     ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
        kafai@...com, songliubraving@...com, yhs@...com,
        john.fastabend@...il.com, kpsingh@...nel.org, sdf@...gle.com,
        haoluo@...gle.com, jolsa@...nel.org, rostedt@...dmis.org,
        mhiramat@...nel.org
Cc:     bpf@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
        linux-kernel@...r.kernel.org, Yafang Shao <laoar.shao@...il.com>
Subject: [PATCH bpf-next 6/6] bpf: Remove some denied functions from the btf id deny list

With the generic tracing recursion prevention mechanism applied, it is
safe to trace migrate_{disable,enable} and preempt_count_{sub,add}. So
we can remove them from the deny list.
However we can't remove rcu_read_unlock_strict and
__rcu_read_{lock,unlock}, because they are used in rcu_read_unlock() or
rcu_read_lock().

Signed-off-by: Yafang Shao <laoar.shao@...il.com>
---
 kernel/bpf/verifier.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 83fb94f..40f6b2c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -18634,17 +18634,9 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
 
 BTF_SET_START(btf_id_deny)
 BTF_ID_UNUSED
-#ifdef CONFIG_SMP
-BTF_ID(func, migrate_disable)
-BTF_ID(func, migrate_enable)
-#endif
 #if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
 BTF_ID(func, rcu_read_unlock_strict)
 #endif
-#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
-BTF_ID(func, preempt_count_add)
-BTF_ID(func, preempt_count_sub)
-#endif
 #ifdef CONFIG_PREEMPT_RCU
 BTF_ID(func, __rcu_read_lock)
 BTF_ID(func, __rcu_read_unlock)
-- 
1.8.3.1