Re: [syzbot] possible deadlock in worker_thread

Bart Van Assche
2022-02-12T16:38:01Z

On 2/11/22 21:31, Tetsuo Handa wrote:
> But this report might be suggesting us that we should consider
> deprecating (and eventually getting rid of) system-wide workqueues
> (declared in include/linux/workqueue.h), for since flush_workqueue()
> synchronously waits for completion, sharing system-wide workqueues
> among multiple modules can generate unexpected locking dependency
> chain (like this report).

I do not agree with deprecating system-wide workqueues. I think that all
flush_workqueue(system_long_wq) calls should be reviewed since these are
deadlock-prone.

Thanks,

Bart.