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From: Baoquan He <bhe@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: mingo@kernel.org, hpa@zytor.com, thgarnie@google.com,
	kirill.shutemov@linux.intel.com, x86@kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
Date: Sat, 8 Sep 2018 21:33:37 +0800	[thread overview]
Message-ID: <20180908133337.GT1740@192.168.1.3> (raw)
In-Reply-To: <alpine.DEB.2.21.1809081410230.1402@nanos.tec.linutronix.de>

On 09/08/18 at 02:10pm, Thomas Gleixner wrote:
> On Wed, 29 Aug 2018, Baoquan He wrote:
> 
> > In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> > initial size of the direct mapping region. This is right in the
> > old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> > 46bit, and only 4-level mode was supported.
> > 
> > Later, in commit:
> > b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> > __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> > 5-level or 4-level. This is wrong for 4-level paging. Then when
> > adapt phyiscal memory region size based on available memory, it
> > will overflow if the amount of system RAM and the padding is bigger
> > than 64TB.
> > 
> > In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> > by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
> > 
> > Signed-off-by: Baoquan He <bhe@redhat.com>
> 
> This lacks a fixes tag .....

Sure, I will add fix tag in this patch, and arrange a new patchset
according to discussion with Kirill after test.

Thanks
Baoquan

      reply	other threads:[~2018-09-08 13:33 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-29  2:17 [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size Baoquan He
2018-08-29  2:17 ` [PATCH 2/2] x86/mm/KASLR: Adjust the vmemmap size according to paging mode Baoquan He
2018-08-29 12:05   ` Kirill A. Shutemov
2018-08-29 12:16     ` Baoquan He
2018-08-29 12:18     ` Baoquan He
2018-08-29 12:26       ` Kirill A. Shutemov
2018-08-29 12:51         ` Baoquan He
2018-08-30 15:25     ` Baoquan He
2018-09-02 20:52       ` Kirill A. Shutemov
2018-09-03  7:47         ` Baoquan He
2018-09-03 10:26           ` Kirill A. Shutemov
2018-09-03 14:52             ` Baoquan He
2018-09-04  8:13               ` Kirill A. Shutemov
2018-09-05  8:15                 ` Baoquan He
2018-09-05 12:09                   ` Kirill A. Shutemov
2018-09-05 12:37                     ` Baoquan He
2018-08-29 11:49 ` [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size Kirill A. Shutemov
2018-09-04 17:57   ` Thomas Garnier
2018-09-08 12:10 ` Thomas Gleixner
2018-09-08 13:33   ` Baoquan He [this message]

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