On Fri, 30 Jan 2026 11:09:26 +0800
Yaxiong Tian [off-list ref] wrote:

quoted

thought|trace_eval_sync()|'s|destroy_workqueue()|would wait for all 
tasks to complete, but it seems that might not be the case. From this, 
if the above conclusion is true, then strictly speaking, tasks 
using|queue_work(xx)|cannot be guaranteed to finish before the init 
process executes. If it's necessary to strictly ensure initialization 
completes before user space starts, 
using|async_synchronize_full()|or|async_synchronize_full_domain()|would 
be better in such scenarios.  

I need to double-check this issue—theoretically, it shouldn't exist. But 
I'm not sure why the print appeared at the 14-second mark.

Use trace_printk() instead. printk now has a "deferred" output. I'm not
sure if the timestamps of when it prints is when the print took place
or when it got to the console :-/

-- Steve

quoted

Of course, the situation described above is an extreme case. I don't 
oppose this approach; I only hope to make the startup faster for 
ordinary users who don’t use trace, while minimizing the impact on 
others as much as possible.