From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Tejun Heo <tj@kernel.org>
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
Bert Karwatzki <spasswolf@web.de>,
Michal Koutny <mkoutny@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
kernel test robot <oliver.sang@intel.com>
Subject: Re: [PATCH v2] cgroup: Wait for dying tasks to leave on rmdir
Date: Wed, 25 Mar 2026 12:52:07 +0100 [thread overview]
Message-ID: <20260325115207.y3WYPLZk@linutronix.de> (raw)
In-Reply-To: <acLxYGxkgPYRP94e@slm.duckdns.org>
On 2026-03-24 10:17:36 [-1000], Tejun Heo wrote:
> Hello,
Hi,
> I'll apply this for now. Can you please try to reproduce the problem with
> the patches applied? How reliably does it reproduce? How is it stuck? Are
> tasks waiting on the waitq indefinitely with populated stuck at 1?
With the patches applied the test suite works. But now I accidentally did
poweroff :
| [ OK ] Finished systemd-poweroff.service - System Power Off.
| [ OK ] Reached target poweroff.target - System Power Off.
| INFO: task systemd:1 blocked for more than 10 seconds.
| Not tainted 7.0.0-rc5+ #167
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
| task:systemd state:D stack:0 pid:1 tgid:1 ppid:0 task_flags:0x400100 flags:0x00080000
| Call Trace:
| <TASK>
| __schedule+0x3d4/0xf80
| schedule+0x27/0xd0
| cgroup_drain_dying+0xb7/0x1b0
| cgroup_rmdir+0x2f/0x100
| kernfs_iop_rmdir+0x6a/0xd0
| vfs_rmdir+0x11a/0x280
| filename_rmdir+0x16f/0x1e0
| __x64_sys_unlinkat+0x58/0x70
| do_syscall_64+0x119/0x5a0
| entry_SYSCALL_64_after_hwframe+0x76/0x7e
| RIP: 0033:0x7f06b8b7fc17
| RSP: 002b:00007ffe37f96c98 EFLAGS: 00000206 ORIG_RAX: 0000000000000107
| RAX: ffffffffffffffda RBX: 000055ee562eba40 RCX: 00007f06b8b7fc17
| RDX: 0000000000000200 RSI: 000055ee562eba53 RDI: 000000000000000c
| RBP: 000000000000000d R08: 000055ee562eba40 R09: 0000000000000000
| R10: 00000000000007a0 R11: 0000000000000206 R12: 000055ee5639daa0
| R13: 0000000000000000 R14: 000055ee562eba53 R15: 000055ee562ec030
| </TASK>
This is not PREEMPT_RT and I can reproduce it also as of commit
6680c162b4850 ("selftests/cgroup: Don't require synchronous populated
update on task exit").
The reboot command is also affected in the same way. systemd is 260-1 in
case it should matter.
> Thanks.
>
Sebastian
next prev parent reply other threads:[~2026-03-25 11:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-23 20:02 [PATCH v2] cgroup: Wait for dying tasks to leave on rmdir Tejun Heo
2026-03-24 9:04 ` Sebastian Andrzej Siewior
2026-03-24 20:17 ` Tejun Heo
2026-03-25 11:52 ` Sebastian Andrzej Siewior [this message]
2026-03-24 20:24 ` Tejun Heo
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