Re: [PATCH net-next 1/9] bpf: prevent kprobe+bpf deadlocks

Daniel Borkmann
2016-03-07T10:08:05Z

On 03/07/2016 02:58 AM, Alexei Starovoitov wrote:
> if kprobe is placed within update or delete hash map helpers
> that hold bucket spin lock and triggered bpf program is trying to
> grab the spinlock for the same bucket on the same cpu, it will
> deadlock.
> Fix it by extending existing recursion prevention mechanism.
>
> Note, map_lookup and other tracing helpers don't have this problem,
> since they don't hold any locks and don't modify global data.
> bpf_trace_printk has its own recursive check and ok as well.
>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>

LGTM

Acked-by: Daniel Borkmann <daniel@iogearbox.net>