From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Baoquan He <bhe@redhat.com>
Cc: tglx@linutronix.de, 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: Wed, 29 Aug 2018 14:49:40 +0300 [thread overview]
Message-ID: <20180829114940.k36272hhxa7fznva@kshutemo-mobl1> (raw)
In-Reply-To: <20180829021754.21850-1-bhe@redhat.com>
On Wed, Aug 29, 2018 at 10:17:53AM +0800, 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>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
next prev parent reply other threads:[~2018-08-29 11:49 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-29 2:17 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 ` Kirill A. Shutemov [this message]
2018-09-04 17:57 ` [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size Thomas Garnier
2018-09-08 12:10 ` Thomas Gleixner
2018-09-08 13:33 ` Baoquan He
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