Re: Race over table->data in proc_do_sync_threshold()

[Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>]

From: Sishuai Gong <sishuai.system@xxxxxxxxx>
Date: Wed, 9 Aug 2023 20:30:37 -0400
> Hi,
> 
> We observed races over (struct ctl_table *) table->data when two threads
> are running proc_do_sync_threshold() in parallel, as shown below:
> 
> Thread-1                      Thread-2
> memcpy(val, valp, sizeof(val)); memcpy(valp, val, sizeof(val));
> 
> This race probably would mess up table->data. Is it better to add a lock?

Yes, we should acquire mutex/seqlock etc.