tree df55e8247ee439a46f498d920a23f6d1b5dce0ad
parent 7deca5eae83389ca40ac1b1bde96e4af17cca84f
author Yafang Shao <laoar.shao@gmail.com> 1682352663 +0000
committer Alexei Starovoitov <ast@kernel.org> 1682370961 -0700

bpf: Add __rcu_read_{lock,unlock} into btf id deny list

The tracing recursion prevention mechanism must be protected by rcu, that
leaves __rcu_read_{lock,unlock} unprotected by this mechanism. If we trace
them, the recursion will happen. Let's add them into the btf id deny list.

When CONFIG_PREEMPT_RCU is enabled, it can be reproduced with a simple bpf
program as such:
  SEC("fentry/__rcu_read_lock")
  int fentry_run()
  {
      return 0;
  }

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230424161104.3737-2-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>