linux-kernel - Re: [PATCH] mm: fix up a spurious page fault whenever it happens

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Message-ID: <51C15F87.20100@meduna.org>
Date:	Wed, 19 Jun 2013 09:36:39 +0200
From:	Stanislav Meduna <stano@...una.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Rik van Riel <riel@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	"linux-rt-users@...r.kernel.org" <linux-rt-users@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	the arch/x86 maintainers <x86@...nel.org>,
	Hai Huang <hhuang@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH] mm: fix up a spurious page fault whenever it happens

On 19.06.2013 07:20, Linus Torvalds wrote:

>> No crash in 2 days running with preempt none...
> 
> Is this UP?

Yes it is.

> There's the fast_tlb race that Peter fixed in commit 29eb77825cc7
> ("arch, mm: Remove tlb_fast_mode()"). I'm not seeing how it would
> cause infinite TLB faults, but it definitely causes potentially
> incoherent TLB contents. And afaik it only happens with
> CONFIG_PREEMPT, and on UP systems. Which sounds like it might match
> your setup...

Oh, thank you for the pointer, this indeed looks interesting.

Unfortunately the patch massively does not apply to 3.4 which
I am using and I know too little what all is involved here
to backport it. I will test it when (if) it gets to the 3.4(-rt)
(or when I find some spare time to play with the newer kernel
on that system).

Thanks
-- 
                                     Stano

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