From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Derek Barbosa <debarbos@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC printk] printk: Postpone kthread startup
Date: Thu, 15 Oct 2026 15:36:08 +0206 [thread overview]
Message-ID: <87bj8vqefz.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <87ecdrqfhw.fsf@jogness.linutronix.de>
On 2026-10-15, John Ogness <john.ogness@linutronix.de> wrote:
> There have been various bug reports related to SMP systems hanging
> on boot. The reports vary wildly but seem to have some overlap with
> regard to missed IPI's during SMP setup. The reports also show that
> reverting NBCON console usage allows the bugs to disappear.
>
> The NBCON kthreads for console printing are started very early
> during boot using early_initcall(). Since these kthreads are
> actively enabling/disabling interrupts during early boot, they may
> be interfering with SMP setup.
>
> Postpone kthread starting until after all arch initcalls have
> completed.
This should also contain:
Reported-by: Derek Barbosa <debarbos@redhat.com>
Closes: https://lore.kernel.org/linux-rt-users/arPmYPbFLf2EldIl@debarbos-thinkpadt14gen5.rmtusma.csb
Fixes: 5f1b414ca027 ("printk: nbcon: Start printing threads")
next prev parent reply other threads:[~2026-10-15 13:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-15 13:07 John Ogness
2026-10-15 13:30 ` John Ogness [this message]
2026-10-16 3:43 ` Derek Barbosa
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