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From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-mm@kvack.org, Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: [BUG -tip] kmemleak and stacktrace cause page faul
Date: Wed, 23 Oct 2019 16:44:13 +0300	[thread overview]
Message-ID: <20191023134413.GI12121@uranus.lan> (raw)
In-Reply-To: <alpine.DEB.2.21.1910231536220.2308@nanos.tec.linutronix.de>

On Wed, Oct 23, 2019 at 03:38:40PM +0200, Thomas Gleixner wrote:
> > > 
> > > [0,2,4,5,6,8,10,12] are guard pages so 0 is not that crappy at all
> > 
> > Wait, Thomas, I might be wrong, but per-cpu is initialized to the pointer,
> > the memory for this estack_pages has not yet been allocated, no?
> 
> static const
> struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {
>         EPAGERANGE(DF),
> 	EPAGERANGE(NMI),
> 	EPAGERANGE(DB1),
> 	EPAGERANGE(DB),
>         EPAGERANGE(MCE),
> };
> 
> It's statically allocated. So it's available from the very beginning.

Indeed, thanks! I happened to overlooked this moment.
...
> And as I explained to you properly decoded the values _ARE_ correct and
> make sense.

Yes, just posted the diff itself to be sure. Thanks a huge for
explanation, Thomas!

  reply	other threads:[~2019-10-23 13:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-19 11:44 [BUG -tip] kmemleak and stacktrace cause page faul Cyrill Gorcunov
2019-10-22 14:23 ` Cyrill Gorcunov
2019-10-22 14:56   ` Cyrill Gorcunov
2019-10-23 13:21     ` Thomas Gleixner
2019-10-23 13:32       ` Cyrill Gorcunov
2019-10-23 13:38         ` Thomas Gleixner
2019-10-23 13:44           ` Cyrill Gorcunov [this message]
2019-10-23 13:47       ` Thomas Gleixner
2019-10-23 13:53         ` Cyrill Gorcunov
2019-10-23 13:59         ` Cyrill Gorcunov
2019-10-23 18:05           ` [PATCH] x86/dumpstack/64: Don't evaluate exception stacks before setup Thomas Gleixner
2019-10-23 18:31             ` Matthew Wilcox
2019-10-23 18:43               ` Cyrill Gorcunov
2019-10-23 21:27               ` Thomas Gleixner
2019-10-23 19:17             ` Josh Poimboeuf
2019-11-04 23:56             ` [tip: x86/urgent] " tip-bot2 for Thomas Gleixner

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