Re: INFO: task hung in fsnotify_connector_destroy_workfn (2)

[Tetsuo Handa]

On 2018/09/25 17:55, Petr Mladek wrote:
>> I guess the patch below fixes it, however the kworker should not really be 
>> blocked by this I think ... adding a few more printk folks to double-check 
>> why the kworker would get stuck due to massive printk() flood.
> 
> It seems that the many printk() calls just delay the entire
> process and rcu gets blocked for too long. The messages are
> the same all the time. So some rate limiting looks like
> a reasonable solution.
> 

Yes. Commit 128f380410350012 ("android: binder: Rate-limit debug and userspace triggered err msgs")
chose ratelimiting as a fix for https://syzkaller.appspot.com/bug?id=0e75779a6f0faac461510c6330514e8f0e893038 .

Since syzbot did not reproduce the problem with Jiri's patch applied,
I think we can apply Jiri's patch as a fix for this problem.