diff options
| author | Yafang Shao <laoar.shao@gmail.com> | 2023-04-24 16:11:03 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-04-24 14:16:01 -0700 |
| commit | a0c109dcafb15b8bee187c49fb746779374f60f0 (patch) | |
| tree | df55e8247ee439a46f498d920a23f6d1b5dce0ad /kernel | |
| parent | 7deca5eae83389ca40ac1b1bde96e4af17cca84f (diff) | |
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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5c4aa393f65a..fbcf5a4e2fcd 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -18671,6 +18671,10 @@ BTF_ID(func, rcu_read_unlock_strict) 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) +#endif BTF_SET_END(btf_id_deny) static bool can_be_sleepable(struct bpf_prog *prog) |