On Thu, Apr 27, 2017 at 1:31 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
> On Wed, Apr 26, 2017 at 2:20 PM, Paul Moore <paul@paul-moore.com> wrote:
>> Thanks for the report, this is the only one like it that I've seen.
>> I'm looking at the code in Linus' tree and I'm not seeing anything
>> obvious ... looking at the trace above it appears that the problem is
>> when get_net() goes to bump the refcount and the passed net pointer is
>> NULL; unless I'm missing something, the only way this would happen in
>> kauditd_thread() is if the auditd_conn.pid value is non-zero but the
>> auditd_conn.net pointer is NULL.
>>
>> That shouldn't happen.
>>
>
> Looking at the code that reads/writes the global auditd_conn,
> I don't see how it even works with RCU+spinlock, RCU plays
> with pointers and you have to make a copy as its name implies.
> But it looks like you simply use RCU+spinlock as a traditional
> rwlock, it doesn't work.

The attached patch seems working for me, I tried to boot my
VM for 4 times, so far no crash or warning.

Please let me know if it looks reasonable to you.