On Fri, 10 Dec 2021 10:20:58 -0800, Davidlohr Bueso wrote:

do_each_pid_thread(PIDTYPE_PGID) can race with a concurrent
change_pid(PIDTYPE_PGID) that can move the task from one hlist
to another while iterating. Serialize ioprio_get to take
the tasklist_lock in this case, just like it's set counterpart.

Applied, thanks!

[1/1] block: fix ioprio_get(IOPRIO_WHO_PGRP) vs setuid(2)
      commit: e6a59aac8a8713f335a37d762db0dbe80e7f6d38

Best regards,
-- 
Jens Axboe