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From: Dave Hansen <dave.hansen@linux.intel.com>
To: "Mike Galbraith" <efault@gmx.de>,
	"Borislav Petkov" <bp@alien8.de>,
	"Jörg Otte" <jrg.otte@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Aaro Koskinen <aaro.koskinen@nokia.com>
Subject: Re: 4.17.0-rc1 doesn't boot.
Date: Tue, 17 Apr 2018 09:48:07 -0700	[thread overview]
Message-ID: <017d65c5-748b-eeae-a020-fa4473f4507c@linux.intel.com> (raw)
In-Reply-To: <1523980839.7093.1.camel@gmx.de>

On 04/17/2018 09:00 AM, Mike Galbraith wrote:
> On Tue, 2018-04-17 at 17:31 +0200, Borislav Petkov wrote:
>> On Tue, Apr 17, 2018 at 05:21:30PM +0200, Jörg Otte wrote:
>>> finished bisection.
>>> 39114b7a743e6759bab4d96b7d9651d44d17e3f9 is the first bad commit
>>> (x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image).
>>
>> Looks like you're not the only one:
>>
>> http://marc.info/?i=20180417150130.GA11166@ak-laptop.emea.nsn-net.net
> 
> I'm hitting this too, but only with PREEMPT_RT.  I put a bandaid on it
> (tell pti_kernel_image_global_ok() to return true for PREEMPT_RT) while
> waiting to see if it was really really as non-rt as it appeared to be.

It looks like pti_init() is too early for
change_page_attr()/set_memory_nonglobal() because they look for
irqs_off().  This *should* be OK in practice because we only need to
flush the boot CPU, not the others.  That's what ends up causing the
BUG_ON().

But, there's apparently something else going on too because things don't
boot even with that BUG_ON() backed out.

The good news is that its easy to reproduce.

  reply	other threads:[~2018-04-17 16:48 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-17  8:00 4.17.0-rc1 doesn't boot Jörg Otte
2018-04-17  8:14 ` Borislav Petkov
2018-04-17 14:16   ` Jörg Otte
2018-04-17 14:27     ` Borislav Petkov
2018-04-17 15:21       ` Jörg Otte
2018-04-17 15:31         ` Borislav Petkov
2018-04-17 16:00           ` Mike Galbraith
2018-04-17 16:48             ` Dave Hansen [this message]
2018-04-17 17:48               ` Mariusz Ceier
2018-04-17 19:56               ` Dave Hansen

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