Race over table->data in proc_do_sync_threshold()

[Sishuai Gong <sishuai.system@xxxxxxxxx>]

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?

Thanks