Hello, On Thu, Nov 14, 2024 at 03:47:58PM +0800, Chen Ridong wrote: > On 2024/11/13 22:34, Valentin Schneider wrote: > > On 11/11/24 13:54, Chen Ridong wrote: > >> From: Chen Ridong <chenridong@xxxxxxxxxx> > >> > >> Before the commit f5d39b020809 ("freezer,sched: Rewrite core freezer > >> logic"), the frozen task stat was reported as 'D' in cgroup v1. > >> However, after rewriting core freezer logic, the frozen task stat is > >> reported as 'R'. This is confusing, especially when a task with stat of > >> 'S' is frozen. > >> > >> This can be reproduced as bellow step: > >> cd /sys/fs/cgroup/freezer/ > >> mkdir test > >> sleep 1000 & > >> [1] 739 // task whose stat is 'S' > >> echo 739 > test/cgroup.procs > >> echo FROZEN > test/freezer.state > >> ps -aux | grep 739 > >> root 739 0.1 0.0 8376 1812 pts/0 R 10:56 0:00 sleep 1000 > >> > >> As shown above, a task whose stat is 'S' was changed to 'R' when it was > >> frozen. To solve this issue, simply maintain the same reported state as > >> before the rewrite. The whole point of the freezer rewrite was preventing userspace from causing arbitrary and indefinite D states which leads to all sorts of problems. The tasks in cgroup2 freezer are *not* in uninterruptible sleeps. They are in task stop loops and thus can be killed, ptraced and so on. It *should* report S. Thanks. -- tejun