From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) (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 9FF0A399021 for ; Tue, 24 Feb 2026 14:20:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771942819; cv=none; b=TJaI7D9Faq6vqepE6gR1pHwEd1qq2nkEfm+vaGHNdRF+5LrPuZ17RyW+7iTQckybS+Wg1VtrNm2HNfgLwTbmKChqkgjPvZ465CZQPdh0xNdom7MeDZrVv05LiOubKIok3S3/uUu6g49Owza128o7gNohnBcHda/uEYeKF1W5IgE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771942819; c=relaxed/simple; bh=/fgIUtbn/ubpDgbXYLiD88WG23C8OSnlkojzMAds5t8=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QMrkeHPvvMV3wq+EJDYsEAxetwyG9vB8pP7S0H5Qo2QNc0ewdbngALIWVX9htMLtqWhQIptOoGpZayt+8lMmzg7+B06LXaLZClLiEcJphNWmTmLVfv85bpoq7RDljC9sTJHI5oYTdoh4zmEbhzHdCL43R7SaGNnerx9VvYjg0hQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 3C11A1B55DF; Tue, 24 Feb 2026 14:20:11 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf08.hostedemail.com (Postfix) with ESMTPA id 9653D20025; Tue, 24 Feb 2026 14:20:08 +0000 (UTC) Date: Tue, 24 Feb 2026 09:20:05 -0500 From: Steven Rostedt To: Bert Karwatzki Cc: Calvin Owens , Tejun Heo , Sebastian Andrzej Siewior , Thomas Gleixner , dschatzberg@meta.com, peterz@infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: ~90s shutdown delay with v6.19 and PREEMPT_RT Message-ID: <20260224092005.01a0cd75@fedora> In-Reply-To: References: <20260219164648.3014-1-spasswolf@web.de> <594b9094ab76acf9e73cad8fca9c9efd6f75a980.camel@web.de> <20260219195851.7a7bd1b2@fedora> <1d56c93ee93334b9d320c93d255d7548f4497836.camel@web.de> <20260220104420.54610b04@gandalf.local.home> <20260223032257.4e6db467@fedora> <80f657156fb2d32d8fe246e65e9ac8bf9d7cfbd5.camel@web.de> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; x86_64-redhat-linux-gnu) 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-Transfer-Encoding: quoted-printable X-Stat-Signature: oc1i4raaqetnrtq4xfcpsk47cyeykfm7 X-Rspamd-Server: rspamout03 X-Rspamd-Queue-Id: 9653D20025 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+E+VCMAV6xz8vykyZOJrFGnN1jBCNmOWI= X-HE-Tag: 1771942808-672914 X-HE-Meta: U2FsdGVkX19TtaZrl6TLZstQQSYazOqZAhXo+2i8NvfiUkMWoQlAZEpc8O8JBpBZfPVo6vpAnaLo5mL7VaPcVYMhD/pKC9P1eCwcDFgAz2koVIpN6oIJgY/m1LqE5o/uOQS58wN5Rtguj0j9/VI9629xnTv4zCNOZGuVJDk3SXIbwUKIK+kOAV890wuSh7dJcmzxukMISeOeDq22jGhyA1u/7KB85EPSkrqNTifStkcYRr1iEDCOP7rbidI8sLetVkoFcZbn+kODt7+nIFC7dTSWAuWrhdiOc2cJ5DqsjI8BSqJqpYVTpakj4stHBIz7pT/EFEnVN8WauyD0Qj2ri8m0F+nVDMdg23QLhQpar9rl8WMvraCH4A== On Tue, 24 Feb 2026 00:36:27 +0100 Bert Karwatzki wrote: > As the bisection in suggested that commit9311e6c29b34 ("cgroup: Fix sleep= ing from invalid context warning on PREEMPT_RT") > is somehow causing the problem I put some printk()s in the code changed b= y this > commit and captured the output via netconsole (I tried using trace_printk= () to > use the persistent ringbuffer but got no output). It's described in the document I posted: https://docs.kernel.org/trace/debugging.html Using trace_printk() in the boot instance By default, the content of trace_printk() goes into the top level tracing instance. But this instance is never preserved across boots. To have the trace_printk() content, and some other internal tracing go to the preserved buffer (like dump stacks), either set the instance to be the trace_printk() destination from the kernel command line, or set it after boot up via the trace_printk_dest option. After boot up: echo 1 > /sys/kernel/tracing/instances/boot_map/options/trace_printk_de= st From the kernel command line: reserve_mem=3D12M:4096:trace trace_instance=3Dboot_map^traceprintk^trac= eoff@trace If setting it from the kernel command line, it is recommended to also disable tracing with the =E2=80=9Ctraceoff=E2=80=9D flag, and enab= le tracing after boot up. Otherwise the trace from the most recent boot will be mixed with the trace from the previous boot, and may make it confusing to read. -- Steve