Re: [syzbot] [cgroups?] INFO: task hung in cgroup_subtree_control_write (2)

[Hillf Danton]

> Date: Mon, 15 Jun 2026 01:05:28 -0700
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    ec039126b7fa Add linux-next specific files for 20260611
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=178e637a580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d0d1fa2afcbce17c
> dashboard link: https://syzkaller.appspot.com/bug?extid=bb2e19a1190a556c01b1
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10b0d4ae580000

#syz test

--- x/kernel/cgroup/cgroup.c
+++ y/kernel/cgroup/cgroup.c
@@ -3267,7 +3267,6 @@ restart:
 			if (!css || !css_is_dying(css))
 				continue;
 
-			cgroup_get_live(dsct);
 			prepare_to_wait(&dsct->offline_waitq, &wait,
 					TASK_UNINTERRUPTIBLE);
 
@@ -3275,7 +3274,6 @@ restart:
 			schedule();
 			finish_wait(&dsct->offline_waitq, &wait);
 
-			cgroup_put(dsct);
 			goto restart;
 		}
 	}
--