diff options
| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2024-02-05 05:56:45 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-02-05 20:00:14 -0800 |
| commit | 6fceea0fa59f6786a2847a4cae409117624e8b58 (patch) | |
| tree | 0756fa0cce159ca3d2eb887f3b4c53fab2e823c5 /kernel/bpf/verifier.c | |
| parent | 8244ab509f89d63941d5ee207967c5a3e00bb493 (diff) | |
bpf: Transfer RCU lock state between subprog calls
Allow transferring an imbalanced RCU lock state between subprog calls
during verification. This allows patterns where a subprog call returns
with an RCU lock held, or a subprog call releases an RCU lock held by
the caller. Currently, the verifier would end up complaining if the RCU
lock is not released when processing an exit from a subprog, which is
non-ideal if its execution is supposed to be enclosed in an RCU read
section of the caller.
Instead, simply only check whether we are processing exit for frame#0
and do not complain on an active RCU lock otherwise. We only need to
update the check when processing BPF_EXIT insn, as copy_verifier_state
is already set up to do the right thing.
Suggested-by: David Vernet <void@manifault.com>
Tested-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20240205055646.1112186-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7d38b2343ad4..ddaf09db1175 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -17703,8 +17703,7 @@ process_bpf_exit_full: return -EINVAL; } - if (env->cur_state->active_rcu_lock && - !in_rbtree_lock_required_cb(env)) { + if (env->cur_state->active_rcu_lock && !env->cur_state->curframe) { verbose(env, "bpf_rcu_read_unlock is missing\n"); return -EINVAL; } |