Possible locking issue in usrloc module in file udomain.c - sr-users

18 Sep 2019


      Hi ,
Currently I am running kamailio 4.2 and now upgrading to kamailio 5.2 and was just going thru the changes.
In the file modules/usrloc/udomain.c inside the function free_udomain( ) , it appears that we are not protecting via lock_ulslot and unlock_ulslot doing free. Could it cause some race condition ?
May be its intentional but going thru the github history its there since day 1. I checked all branches in kamailio 4.x and we have the protection.
In 4.x
void free_udomain(udomain_t* _d)
{
    int i;
    
    if (_d->table) {
        for(i = 0; i < _d->size; i++) {
            lock_ulslot(_d, i);
            deinit_slot(_d->table + i);
            unlock_ulslot(_d, i);
        }
        shm_free(_d->table);
    }    shm_free(_d);
}
In 5.x
void free_udomain(udomain_t* _d)
{
    int i;
    
    if (_d->table) {
        for(i = 0; i < _d->size; i++) {
            deinit_slot(_d->table + i);
        }
        shm_free(_d->table);
    }
    shm_free(_d);
}