Re: [PATCH] ima: fix infinite loop within "ima_match_policy" function.

Hi Liqiong,

On Mon, 2021-08-23 at 11:04 +0800, 李力琼 wrote:

Hi Mimi :

The situation is a little different,'list_splice_init_rcu'
don't change the list head. If "ima_rules" being changed,
readers may can't reload the new value in time for cpu cache
or compiler optimization. Defining "ima_rules" as a volatile 
variable can fix, but It is inefficient.

After looking at list_splice_tail_init_rcu() some more, it is
actually making sure there aren't any readers traversing
"ima_temp_rules", not "ima_policy_rules".   There aren't any readers
traversing "ima_temp_rules". 

Maybe using a temporary ima_rules variable for every 
"list_for_each_entry_rcu(entry, ima_rules, list)" loop is 
a better solution to fix the "endless loop" bug. 

Agreed

thanks,

Mimi