In the Linux kernel, the following vulnerability has been resolved: bpf: Allow LPM map access from sleepable BPF programs trie_lookup_elem() annotates its rcu_dereference_check() walks with only rc…

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Allow LPM map access from sleepable BPF programs trie_lookup_elem() annotates its rcu_dereference_check() walks with only rcu_read_lock_bh_held(). Because rcu_dereference_check(p, c) resolves to "c || rcu_read_lock_held()", this passes for XDP/NAPI and classic RCU readers but fails for sleepable BPF programs, which enter via __bpf_prog_enter_sleepable() and hold only rcu_read_lock_trace(). trie_update_elem() and trie_d…