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From: Leon Romanovsky <leon@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
	x86 <x86@kernel.org>, Suresh Siddha <suresh.b.siddha@intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/apic: Fix circular locking dependency between console and hrtimer locks
Date: Mon, 27 Apr 2020 18:54:10 +0300	[thread overview]
Message-ID: <20200427155410.GG134660@unreal> (raw)
In-Reply-To: <87y2qhoshi.fsf@nanos.tec.linutronix.de>

On Mon, Apr 27, 2020 at 05:31:21PM +0200, Thomas Gleixner wrote:
> Leon Romanovsky <leon@kernel.org> writes:
> > OK, I consulted with verification people and back then the trigger was:
> > Reproduce when run "echo 1 > /sys/kernel/debug/clear_warn_once" after
> > reboot
>
> That explains it.
>
> > [    0.937310] Freeing SMP alternatives memory: 32K
> > [    0.940471] TSC deadline timer enabled
>
> So here is the first one which sets 'once'. Of course if you clear 'once'
> afterwards then this triggers because the context is completely
> different.
>
> So the right thing to do is to move this out of __setup_APIC_LVTT() and
> be done with it.

Thanks a lot.

  reply	other threads:[~2020-04-27 15:54 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-07 17:09 [PATCH] x86/apic: Fix circular locking dependency between console and hrtimer locks Leon Romanovsky
2020-04-14  5:48 ` Leon Romanovsky
2020-04-14  6:24   ` Ingo Molnar
2020-04-14  7:05     ` Leon Romanovsky
2020-04-23  7:13       ` Leon Romanovsky
2020-04-27 15:35       ` Thomas Gleixner
2020-04-27 15:49         ` Leon Romanovsky
2020-04-27 11:09     ` Thomas Gleixner
2020-04-27 11:32       ` Leon Romanovsky
2020-04-27 12:59         ` Thomas Gleixner
2020-04-27 13:41           ` Leon Romanovsky
2020-04-27 15:31             ` Thomas Gleixner
2020-04-27 15:54               ` Leon Romanovsky [this message]
2020-05-01 18:22               ` [tip: x86/urgent] x86/apic: Move TSC deadline timer debug printk tip-bot2 for Thomas Gleixner

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