From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A0A83CF661; Wed, 25 Mar 2026 11:52:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774439533; cv=none; b=SWkL3hBT7GkV6BAYjLuCaOIOtkwORX/HXxZ3B4XYvPryNxTfemQYHCOovPXcYHTtPE/e8yaMeXLhU7hHs4cfC/9ZlRW9CxZj/c1WcLUzIs3wn7Lxlf2tIMjpOJksGufflaAqn02omUel5d01T3BXE+SHLSf2LRpAs+2vhkBOp2U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774439533; c=relaxed/simple; bh=+aDTUeQQn9wZslL6TzmMIw8i+6rixsxpnOc0bGWhBPM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LMOQbAOExC6Rf29TkouIJKgcaOnDcaGfNZaMZ7awiV4rErzF/dqLzCQuGsix0aVTMNRbojheC5LZmqn1ADFL5U+f2XgP0+b98cm/a4pnAXpm9smmSVG+ypikIAMvBKnFRBdXeaLDdDBzRIXwD/1PfKMqdV8r/p0fpNj5/YkFvAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=YZhINbLE; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=gfW+tRjs; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="YZhINbLE"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="gfW+tRjs" Date: Wed, 25 Mar 2026 12:52:07 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1774439528; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=TmzCdllCY1cSQI/BPmhqvFc3tOR6AYvQqHpqIOkdB6s=; b=YZhINbLEb3/umtq/7pTw859yD5Pjh/KNXpuEP2bhncHICkCypvXg1SRctOMpttNXnZjeGi +8fxqBH1ZbtID2Z791CGnoqa2hZSk057WsEd+/pZp18odOE421l+2K3/a9yFKSmfBaIOm2 bGU5Dom2fepjKotzHTo/bDAZ34x1KaHeIkpS3cM+L+taz/EW0wtYILG8NSvKDc+C+ces3W 88t3p3kUuSJjFwg9xIyBoxBuowJDV5XO7wYDIz7GlCz0yfZaKoM4AUp7pBj85jWO4JWluN ze7J7rz9Q3qBHL8lOG/PoEJeX1keJ+dlCKm0o8xyzp0wTCFkIkCVrQ0m1xGkgw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1774439528; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=TmzCdllCY1cSQI/BPmhqvFc3tOR6AYvQqHpqIOkdB6s=; b=gfW+tRjsNpLZi9xjYmeFTTrLKUXIR1lSa+uoV70Hj6DM7CZygTBRrAWDQktvCfeb4ofgQq s3CjyNPKUca+7VDw== From: Sebastian Andrzej Siewior To: Tejun Heo Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Bert Karwatzki , Michal Koutny , Johannes Weiner , kernel test robot Subject: Re: [PATCH v2] cgroup: Wait for dying tasks to leave on rmdir Message-ID: <20260325115207.y3WYPLZk@linutronix.de> References: <20260323200205.1063629-1-tj@kernel.org> <20260324090402.k7NkNcEp@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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: | | __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 | 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